usb: phy: twl6030-usb: Include linux/of.h header

'of_match_ptr' is defined in linux/of.h. Include it explicitly to
avoid build breakage in the future.
Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/phy/phy-twl6030-usb.c

@@ -33,6 +33,7 @@
 #include <linux/err.h>
 #include <linux/slab.h>
 #include <linux/delay.h>
+#include <linux/of.h>
 
 /* usb register definitions */
 #define USB_VENDOR_ID_LSB		0x00