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/watchdog/twl4030_wdt.c b/drivers/watchdog/twl4030_wdt.c
index 20968b2..8162a40 100644
--- a/drivers/watchdog/twl4030_wdt.c
+++ b/drivers/watchdog/twl4030_wdt.c
@@ -48,7 +48,7 @@
 
 static int twl4030_wdt_write(unsigned char val)
 {
-	return twl4030_i2c_write_u8(TWL4030_MODULE_PM_RECEIVER, val,
+	return twl_i2c_write_u8(TWL4030_MODULE_PM_RECEIVER, val,
 					TWL4030_WATCHDOG_CFG_REG_OFFS);
 }