turnip: Only write the tu_RegisterDeviceEXT() out fence on success.

Fixes a double-free in dEQP-VK.wsi.display_control.register_device_event
where the fence that we destroyed got destroyed again.  Leaving it unset
in the error path leaves the test's NULL in place.

Part-of: <!10473>
58 jobs for !10473 with turnip-wsi-double-free in 21 minutes and 29 seconds (queued for 4 seconds)
latest detached
Status Job ID Name Coverage
  Sanity
passed sanity #9248024

00:00:08

 
  Container
passed arm_build #9248029
aarch64

00:00:19

passed windows_build_vs2019 #9248031
windows shell 1809 mesa

00:00:08

passed x86_build-base #9248025

00:00:19

passed x86_test-base #9248027

00:00:23

 
  Container 2
passed android_build #9248040

00:00:20

passed i386_build #9248035

00:00:20

passed kernel+rootfs_amd64 #9248045

00:00:20

passed kernel+rootfs_arm64 #9248047
aarch64

00:01:05

passed kernel+rootfs_armhf #9248049
aarch64

00:00:11

passed ppc64el_build #9248037

00:00:24

passed s390x_build #9248038

00:00:23

passed x86_build #9248033

00:00:24

passed x86_test-gl #9248042

00:00:30

passed x86_test-vk #9248044

00:00:30

 
  Meson X86 64
passed meson-clang #9248059

00:04:20

passed meson-clover #9248060

00:02:44

passed meson-clover-testing #9248054

00:02:58

passed meson-gallium #9248055

00:04:23

passed meson-release #9248057

00:03:03

passed meson-testing #9248051

00:02:02

passed meson-testing-asan #9248052

00:02:56

passed meson-vulkan #9248062

00:01:40

 
  Build Misc
passed arm_test #9248064

00:00:39

passed meson-android #9248065

00:00:45

passed meson-arm64 #9248069
aarch64

00:01:19

passed meson-arm64-asan #9248071
aarch64

00:03:36

passed meson-arm64-build-test #9248072
aarch64

00:01:27

passed meson-armhf #9248067
aarch64

00:01:42

passed meson-i386 #9248075

00:02:42

passed meson-mingw32-x86_64 #9248080

00:02:40

passed meson-ppc64el #9248078

00:03:24

passed meson-s390x #9248076
kvm

00:03:26

 
  Freedreno
passed a306_gles2 #9248081
google-freedreno-db410c

00:04:39

passed a306_gles3 1/3 #9248083
google-freedreno-db410c

00:08:57

passed a306_gles3 2/3 #9248085
google-freedreno-db410c

00:08:46

passed a306_gles3 3/3 #9248087
google-freedreno-db410c

00:08:36

passed a306_gles3_options #9248089
google-freedreno-db410c

00:03:41

passed a306-traces #9248091
google-freedreno-db410c

00:08:34

passed a530_gles2 #9248093
google-freedreno-db820c

00:05:13

passed a530_gles31 1/2 #9248099
google-freedreno-db820c

00:05:19

passed a530_gles3 1/2 #9248095
google-freedreno-db820c

00:07:40

passed a530_gles31 2/2 #9248101
google-freedreno-db820c

00:05:31

passed a530_gles3 2/2 #9248097
google-freedreno-db820c

00:07:58

passed a530_piglit_gl #9248103
google-freedreno-db820c

00:09:27

passed a530_piglit_shader #9248105
google-freedreno-db820c

00:07:39

passed a530-traces #9248107
google-freedreno-db820c

00:13:55

passed a630_egl #9248117
google-freedreno-cheza

00:02:01

passed a630_gl #9248115
google-freedreno-cheza

00:01:18

passed a630_gles2 #9248109
google-freedreno-cheza

00:01:25

passed a630_gles3 #9248113
google-freedreno-cheza

00:04:31

passed a630_gles31 #9248111
google-freedreno-cheza

00:03:48

passed a630_gles_others #9248119
google-freedreno-cheza

00:02:38

passed a630_piglit #9248127
google-freedreno-cheza

00:09:19

passed a630-traces #9248129
google-freedreno-cheza

00:08:09

passed a630_vk 1/2 #9248121
google-freedreno-cheza

00:10:18

passed a630_vk 2/2 #9248123
google-freedreno-cheza

00:11:08

passed a630_vk_sysmem #9248125
google-freedreno-cheza

00:02:08