V4L/DVB (10129): dvb: remove deprecated use of RW_LOCK_UNLOCKED in frontends

Impact: clean up

RW_LOCK_UNLOCKED is deprecated.  This patch replaces it with the
__RW_LOCK_UNLOCKED(lock) macro.  This change was a little trickier than
others due to the macro being used in another macro that fills an array.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>