wip: gallium: enable EGL_EXT_image_dma_buf_import_modifiers unconditionally

Or at least, enable it if you support _image_dma_buf_import. The
advantage of doing so, even if you support no modifiers, is that the
app can call eglQueryDmaBufFormatsEXT to discover the list of supported
formats.
22 jobs for !1812 with unconditional-import-modifiers in 81 minutes and 40 seconds (queued for 48 minutes and 20 seconds)
latest detached
Status Job ID Name Coverage
  Containers Build
passed #550853
debian

00:00:23

 
  Build+Test
passed #550862
meson-arm64

00:03:24

passed #550861
meson-armhf

00:03:22

passed #550855
meson-clang

00:06:12

passed #550859
meson-clover

00:07:14

passed #550863
meson-i386

00:04:27

passed #550858
meson-main

00:04:09

passed #550854
meson-swr-glvnd

00:03:24

passed #550860
meson-vulkan

00:03:06

passed #550865
scons-llvm

00:05:42

passed #550864
scons-nollvm

00:03:46

passed #550856
scons-swr

00:04:50

passed #550857
scons-win64

00:03:58

 
  Test
passed #550866
test-llvmpipe-gles2 1/4

00:04:04

passed #550867
test-llvmpipe-gles2 2/4

00:04:18

passed #550868
test-llvmpipe-gles2 3/4

00:03:49

passed #550869
test-llvmpipe-gles2 4/4

00:03:51

passed #550870
test-softpipe-gles2 1/4

00:02:00

passed #550871
test-softpipe-gles2 2/4

00:01:35

passed #550872
test-softpipe-gles2 3/4

00:01:30

passed #550873
test-softpipe-gles2 4/4

00:01:59

passed #550874
test-softpipe-gles3-limited

00:04:27