mfd: Include <linux/gpio.h> instead of <asm/gpio.h>

As warned by checkpatch.pl, use #include <linux/gpio.h> instead
of <asm/gpio.h>.
Signed-off-by: Axel Lin <axel.lin@gmail.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

drivers/mfd/tps65010.c

@@ -34,7 +34,7 @@
 
 #include <linux/i2c/tps65010.h>
 
-#include <asm/gpio.h>
+#include <linux/gpio.h>
 
 
 /*-------------------------------------------------------------------------*/