staging: vchiq_arm: Include linux/mm.h

vchiq_2835_arm.c uses functions and macros like put_page() or
PAGE_ALIGN(). So we better include the necessary header.
Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c

@@ -40,6 +40,7 @@
 #include <linux/io.h>
 #include <linux/platform_device.h>
 #include <linux/uaccess.h>
+#include <linux/mm.h>
 #include <linux/of.h>
 #include <soc/bcm2835/raspberrypi-firmware.h>