mtd: OneNAND: OMAP2/3: free GPMC CS on module removal

GPMC CS was not freed in omap2_onenand_remove() preventing the module
from reloading after removal.

Signed-off-by: Mika Korhonen <[e-mail]>
Signed-off-by: Artem Bityutskiy <[e-mail]>
Signed-off-by: David Woodhouse <[e-mail]>

drivers/mtd/onenand/omap2.c

···
 	}
 	iounmap(c->onenand.base);
 	release_mem_region(c->phys_base, ONENAND_IO_SIZE);
+	gpmc_cs_free(c->gpmc_cs);
 	kfree(c);
 
 	return 0;