media: use pci_zalloc_consistent

Remove the now unnecessary memset too.

Signed-off-by: Joe Perches <joe@perches.com>
Cc: Hans Verkuil <hverkuil@xs4all.nl>
Cc: Mauro Carvalho Chehab <m.chehab@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>