Make drmmode_crtc_scanout_create/destroy static

And the latter inline.
12 jobs for drmmode-scanout-cleanups in 1 minute and 37 seconds (queued for 1 second)
Status Job ID Name Coverage
  Docker Image
passed #2845317
container-build

00:00:32

 
  Build
passed #2845320
xserver-1.13

00:00:30

passed #2845321
xserver-1.14

00:00:58

passed #2845322
xserver-1.15

00:00:34

passed #2845323
xserver-1.16

00:01:00

passed #2845324
xserver-1.17

00:00:34

passed #2845325
xserver-1.18

00:00:34

passed #2845326
xserver-1.18-clang

00:01:01

passed #2845327
xserver-1.19

00:00:34

passed #2845328
xserver-1.19-clang

00:00:38

passed #2845318
xserver-1.20

00:00:38

passed #2845319
xserver-1.20-clang

00:00:33