mfd: arizona: Include linux/of.h header

'of_match_ptr' is defined in linux/of.h. Include it explicitly to
avoid breakage in the future.
Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

drivers/mfd/arizona-i2c.c

@@ -17,6 +17,7 @@
 #include <linux/regmap.h>
 #include <linux/regulator/consumer.h>
 #include <linux/slab.h>
+#include <linux/of.h>
 
 #include <linux/mfd/arizona/core.h>
 

drivers/mfd/arizona-spi.c

@@ -17,6 +17,7 @@
 #include <linux/regulator/consumer.h>
 #include <linux/slab.h>
 #include <linux/spi/spi.h>
+#include <linux/of.h>
 
 #include <linux/mfd/arizona/core.h>