gma500: silence gcc warnings in mid_get_vbt_data()

Add a cast here to silence a Gcc warning.
drivers/gpu/drm/gma500/mid_bios.c:214:28: warning:
cast from pointer to integer of different size [-Wpointer-to-int-cast]

Signed-off-by: Dan Carpenter <[e-mail]>
Acked-by: Alan Cox <[e-mail]>
Signed-off-by: Dave Airlie <[e-mail]>

drivers/gpu/drm/gma500/mid_bios.c

···
 		/*so, some values have changed location*/
 		new_size = vbt->checksum; /*checksum contains lo size byte*/
 		/*LSB of oaktrail_gct contains hi size byte*/
-		new_size |= ((0xff & (unsigned int)vbt->oaktrail_gct)) << 8;
+		new_size |= ((0xff & (unsigned int)(long)vbt->oaktrail_gct)) << 8;
 
 		vbt->checksum = vbt->size; /*size contains the checksum*/
 		if (new_size > 0xff)
···
 			vbt->size = new_size;
 
 		/* number of descriptors defined in the GCT */
-		number_desc = ((0xff00 & (unsigned int)vbt->oaktrail_gct)) >> 8;
-		bpi = ((0xff0000 & (unsigned int)vbt->oaktrail_gct)) >> 16;
+		number_desc = ((0xff00 & (unsigned int)(long)vbt->oaktrail_gct)) >> 8;
+		bpi = ((0xff0000 & (unsigned int)(long)vbt->oaktrail_gct)) >> 16;
 		vbt->oaktrail_gct = ioremap(addr + GCT_R10_HEADER_SIZE,
 				GCT_R10_DISPLAY_DESC_SIZE * number_desc);
 		pGCT = vbt->oaktrail_gct;