Since commit da6e162d ("[media] rc-core: simplify sysfs code"), when
the IR protocol is set using the sysfs interface to the same set of
protocols that are already set, store_protocols() does not refresh the
scancode filter with the new protocol, even if it has already called the
change_protocol() callback successfully. This results in the filter
being disabled in the hardware and not re-enabled until the filter is
set again using sysfs.

Fix in store_protocols() by still re-applying the filter whenever the
change_protocol() driver callback succeeded.

The problem can be reproduced with the img-ir driver by setting a
filter, and then setting the protocol to the same protocol that is
already set:
$ echo nec > protocols
$ echo 0xffff > filter_mask
$ echo nec > protocols

After this, messages which don't match the filter were still being
received.

Fixes: da6e162d ("[media] rc-core: simplify sysfs code")
Reported-by: Sifan Naeem <sifan.naeem@imgtec.com>
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: David Härdeman <david@hardeman.nu>
Cc: <stable@vger.kernel.org> # v3.17+
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>