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 Name Job ID Coverage
  Docker Image
passed container-build #2845317

00:00:32

 
  Build
passed xserver-1.13 #2845320

00:00:30

passed xserver-1.14 #2845321

00:00:58

passed xserver-1.15 #2845322

00:00:34

passed xserver-1.16 #2845323

00:01:00

passed xserver-1.17 #2845324

00:00:34

passed xserver-1.18 #2845325

00:00:34

passed xserver-1.18-clang #2845326

00:01:01

passed xserver-1.19 #2845327

00:00:34

passed xserver-1.19-clang #2845328

00:00:38

passed xserver-1.20 #2845318

00:00:38

passed xserver-1.20-clang #2845319

00:00:33