v4l2slh264dec: Fix slice header bit size calculation

The emulation bytes need to be removed as bytes, not bit. This fixes
decoding issues with files that have emulation bytes with the Cedrus
driver.

Part-of: <gstreamer/gst-plugins-bad!2472>
29 jobs for !2472 with backport-mr-2471-into-1.18-cedrus-header-bit-size in 34 minutes and 11 seconds (queued for 7 seconds)
detached
Status Name Job ID Coverage
  Build Docker
passed alpine amd64 manifest builder docker #12911776

00:00:46

passed android docker #12911775

00:00:49

passed cerbero fedora amd64 docker #12911774

00:00:50

passed fedora amd64 docker #12911773

00:00:50

passed gst-indent amd64 docker #12911777

00:00:33

 
  Preparation
passed gst indent #12911779

00:00:12

passed manifest #12911778

00:00:18

 
  Build
passed build cerbero cross-android universal #12911788
gstreamer

00:15:39

passed build cerbero cross-ios universal #12911792
gst-ios-14.3

00:26:05

passed build cerbero cross win32 #12911789
gstreamer

00:06:29

passed build cerbero cross win64 #12911790
gstreamer

00:06:31

passed build cerbero fedora x86_64 #12911787
gstreamer

00:06:13

passed build cerbero macos x86_64 #12911791
gst-macos-11.1

00:15:02

passed build clang fedora x86_64 #12911783

00:07:22

manual build msys2 #12911786
docker windows 1809 allowed to fail manual
passed build nodebug fedora x86_64 #12911780

00:07:24

passed build static fedora x86_64 #12911781

00:07:24

passed build static nodebug fedora x86_64 #12911782

00:07:23

passed build vs2017 amd64 #12911784
docker windows 1809

00:11:16

passed build vs2017 x86 #12911785
docker windows 1809

00:10:59

 
  Test
passed check fedora #12911793
gstreamer

00:08:04

passed integration testsuites fedora 1/4 #12911794
gstreamer

00:08:44

passed integration testsuites fedora 2/4 #12911795
gstreamer

00:10:40

passed integration testsuites fedora 3/4 #12911796
gstreamer

00:10:32

passed integration testsuites fedora 4/4 #12911797
gstreamer

00:10:11

passed valgrind bad #12911798
gstreamer

00:09:18

 
  Integrate
passed cross-android universal examples #12911799

00:05:56

passed cross-ios universal examples #12911801
gst-ios-14.3

00:06:46

passed documentation #12911800

00:11:53