mfd: mc13xxx: Don't require lock for simple register I/O

Since the conversion to regmap there has been no need for device level
locking for I/O as regmap provides locking so remove the locks.
Signed-off-by: Mark Brown <broonie@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

drivers/mfd/mc13xxx-core.c

@@ -158,8 +158,6 @@ int mc13xxx_reg_read(struct mc13xxx *mc13xxx, unsigned int offset, u32 *val)
 {
 	int ret;
 
-	BUG_ON(!mutex_is_locked(&mc13xxx->lock));
-
 	if (offset > MC13XXX_NUMREGS)
 		return -EINVAL;
 
@@ -172,8 +170,6 @@ EXPORT_SYMBOL(mc13xxx_reg_read);
 
 int mc13xxx_reg_write(struct mc13xxx *mc13xxx, unsigned int offset, u32 val)
 {
-	BUG_ON(!mutex_is_locked(&mc13xxx->lock));
-
 	dev_vdbg(mc13xxx->dev, "[0x%02x] <- 0x%06x\n", offset, val);
 
 	if (offset > MC13XXX_NUMREGS || val > 0xffffff)
@@ -186,7 +182,6 @@ EXPORT_SYMBOL(mc13xxx_reg_write);
 int mc13xxx_reg_rmw(struct mc13xxx *mc13xxx, unsigned int offset,
 		u32 mask, u32 val)
 {
-	BUG_ON(!mutex_is_locked(&mc13xxx->lock));
 	BUG_ON(val & ~mask);
 	dev_vdbg(mc13xxx->dev, "[0x%02x] <- 0x%06x (mask: 0x%06x)\n",
 			offset, val, mask);