mfd: Rename all twl4030_i2c*

This patch renames function names like twl4030_i2c_write_u8,
twl4030_i2c_read_u8 to twl_i2c_write_u8, twl_i2c_read_u8
and also common variable in twl-core.c

Signed-off-by: Rajendra Nayak <rnayak@ti.com>
Signed-off-by: Balaji T K <balajitk@ti.com>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Acked-by: Kevin Hilman <khilman@deeprootsystems.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
diff --git a/drivers/input/keyboard/twl4030_keypad.c b/drivers/input/keyboard/twl4030_keypad.c
index 1d1536a..eeaa7ac 100644
--- a/drivers/input/keyboard/twl4030_keypad.c
+++ b/drivers/input/keyboard/twl4030_keypad.c
@@ -133,7 +133,7 @@
 static int twl4030_kpread(struct twl4030_keypad *kp,
 		u8 *data, u32 reg, u8 num_bytes)
 {
-	int ret = twl4030_i2c_read(TWL4030_MODULE_KEYPAD, data, reg, num_bytes);
+	int ret = twl_i2c_read(TWL4030_MODULE_KEYPAD, data, reg, num_bytes);
 
 	if (ret < 0)
 		dev_warn(kp->dbg_dev,
@@ -145,7 +145,7 @@
 
 static int twl4030_kpwrite_u8(struct twl4030_keypad *kp, u8 data, u32 reg)
 {
-	int ret = twl4030_i2c_write_u8(TWL4030_MODULE_KEYPAD, data, reg);
+	int ret = twl_i2c_write_u8(TWL4030_MODULE_KEYPAD, data, reg);
 
 	if (ret < 0)
 		dev_warn(kp->dbg_dev,