[media] media: vb2: review mem_priv usage and fix potential bugs
[media] media: vb2: review mem_priv usage and fix potential bugs

This patch is a result of review of mem_priv entry usage in videobuf2 core.
It fixes all all potential places where it was not checked against NULL or
zeroed after freeing as well as a few style issues.

Signed-off-by: Marek Szyprowski <2a0259761cc3e88db42be5300c1579a67c77e65e@samsung.com>
Signed-off-by: Kyungmin Park <504c23c4986a3760712724894be3105092c27331@samsung.com>
CC: Pawel Osciak <5564a40b3044389cdd055bde6a926496e668fbf8@osciak.com>
Signed-off-by: Mauro Carvalho Chehab <ad86ba2154032c9f55743a190faa2459a9d61d42@redhat.com>

TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs