[media] rc: sunxi-cir: Initialize the spinlock properly

The driver allocates the spinlock but fails to initialize it correctly.
The kernel reports a BUG indicating bad spinlock magic when spinlock
debugging is enabled.

Call spin_lock_init() on it to initialize it correctly.

Fixes: b4e3e59f ("[media] rc: add sunxi-ir driver")

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>