Use regcache_{set,get}_val in regcache_rbtree_{set,get}_register instead of
re-implementing its functionality.
Signed-off-by: NLars-Peter Clausen <lars@metafoo.de>
Acked-by: NDimitris Papastamos <dp@opensource.wolfsonmicro.com>
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>