video-converter: Remove unused variable/calculation

Since the refactoring in cdd86d02
calculating the stride was no longer needed in setup_scale.
6 jobs for scanbuildfixes in 30 minutes and 56 seconds (queued for 20 minutes and 41 seconds)
Status Job ID Name Coverage
  Preparation
passed #65234
gst indent

00:00:29

passed #65233
manifest

00:00:21

 
  Build
passed #65235
build fedora x86_64

00:02:56

 
  Test
passed #65236
check fedora

00:15:19

 
  Full Builds
passed #65237
build android arm64 api28

00:03:06

passed #65238
build cerbero fedora x86_64

00:10:20