cpm2: Fix race condition in CPM2 GPIO library.

The CPM2 GPIO library code uses the non thread-safe clrbits32/setbits32
macros. This patch protects them with a spinlock.

Signed-off-by: Laurent Pinchart <laurentp@cse-semaphore.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>