msdk: Fix invalid return type build warning

void function cannot have return value

gst-plugins-bad/sys/msdk/gstmsdkbufferpool.c(332): warning C4098:
'gst_msdk_buffer_pool_release_buffer': ...
6 jobs for fix-msdk in 27 minutes and 32 seconds
Status Job ID Name Coverage
  Preparation
passed #69539
gst indent

00:00:30

passed #69538
manifest

00:00:33

 
  Build
passed #69540
build fedora x86_64

00:03:21

 
  Test
passed #69541
check fedora

00:14:20

 
  Full Builds
passed #69542
build android arm64 api28

00:05:25

passed #69543
build cerbero fedora x86_64

00:09:16