mfd: twl6040: Remove duplicate inclusion of linux/err.h

linux/err.h was included twice.
Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

drivers/mfd/twl6040.c

@@ -37,7 +37,6 @@
 #include <linux/delay.h>
 #include <linux/i2c.h>
 #include <linux/regmap.h>
-#include <linux/err.h>
 #include <linux/mfd/core.h>
 #include <linux/mfd/twl6040.h>
 #include <linux/regulator/consumer.h>