usb: gadget: rndis: init & exit rndis at module load/unload

This is required in preparation for using usb_gstrings_attach.

The rndis initialization so far has been performed on the first
occurence of rndis_bind(), but the condition to check it (first
or not first) was "borrowed" from strings handling.

Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/gadget/rndis.c

@@ -1174,7 +1174,7 @@ int rndis_init(void)
 
 	return 0;
 }
-EXPORT_SYMBOL(rndis_init);
+module_init(rndis_init);
 
 void rndis_exit(void)
 {
@@ -1188,6 +1188,6 @@ void rndis_exit(void)
 	}
 #endif
 }
-EXPORT_SYMBOL(rndis_exit);
+module_exit(rndis_exit);
 
 MODULE_LICENSE("GPL");