regmap: Provide __acquires/__releases annotations

Fix the following sparse warnings:

drivers/base/regmap/regmap.c:305:13: warning: context imbalance in 'regmap_lock_spinlock' - wrong count at exit
drivers/base/regmap/regmap.c:314:13: warning: context imbalance in 'regmap_unlock_spinlock' - unexpected unlock

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
index 95920583..bf8a81c 100644
--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c
@@ -303,6 +303,7 @@
 }
 
 static void regmap_lock_spinlock(void *__map)
+__acquires(&map->spinlock)
 {
 	struct regmap *map = __map;
 	unsigned long flags;
@@ -312,6 +313,7 @@
 }
 
 static void regmap_unlock_spinlock(void *__map)
+__releases(&map->spinlock)
 {
 	struct regmap *map = __map;
 	spin_unlock_irqrestore(&map->spinlock, map->spinlock_flags);