vaapipostproc: fix csc fail when only change width or height.

6 jobs for csc_fail in 29 minutes and 25 seconds (queued for 1 second)
Status Name Job ID Coverage
  Preparation
passed gst indent #64792

00:00:23

passed manifest #64791

00:00:26

 
  Build
passed build fedora x86_64 #64793

00:03:28

 
  Test
passed check fedora #64794

00:15:33

 
  Full Builds
passed build android arm64 api28 #64795

00:03:07

passed build cerbero fedora x86_64 #64796

00:09:57