[media] blackfin: add error frame support

Mark current frame as error frame when ppi error interrupt
report fifo error. Member next_frm in struct bcap_device can
be optimized out.

Signed-off-by: Scott Jiang <scott.jiang.linux@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>