USB: g_mass_storage: Mass Storage Function created

The f_mass_storage.c has been changed into a composite function.
mass_storage.c file has been introduced which defines a
g_mass_storage gadget based on composite framework.

Signed-off-by: Michal Nazarewicz <m.nazarewicz@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/usb/gadget/file_storage.c b/drivers/usb/gadget/file_storage.c
index 7998402..fca3407 100644
--- a/drivers/usb/gadget/file_storage.c
+++ b/drivers/usb/gadget/file_storage.c
@@ -594,10 +594,9 @@
 
 	if (gadget_is_dualspeed(gadget) && type == USB_DT_OTHER_SPEED_CONFIG)
 		speed = (USB_SPEED_FULL + USB_SPEED_HIGH) - speed;
-	if (gadget_is_dualspeed(gadget) && speed == USB_SPEED_HIGH)
-		function = fsg_hs_function;
-	else
-		function = fsg_fs_function;
+	function = gadget_is_dualspeed(gadget) && speed == USB_SPEED_HIGH
+		? (const struct usb_descriptor_header **)fsg_hs_function
+		: (const struct usb_descriptor_header **)fsg_fs_function;
 
 	/* for now, don't advertise srp-only devices */
 	if (!gadget_is_otg(gadget))