NET: sb1250-mac: Add missing MODULE_LICENSE()

As per comment, the code has always been GPLv2 licensed.

This fixes the follwoing modpost warning:

WARNING: modpost: missing MODULE_LICENSE() in drivers/net/ethernet/broadcom/sb1250-mac.o

Signed-off-by: Ralf Baechle <[e-mail]>

drivers/net/ethernet/broadcom/sb1250-mac.c

···
 };
 
 module_platform_driver(sbmac_driver);
+MODULE_LICENSE("GPL");