soc/intel/broadwell: Change variable back to u32

commit bde6d309df (x86: Change MMIO addr in
readN(addr)/writeN(addr, val) to pointer) accidentally changed
the type of reg32 to a u8 *, so change it back to a u32.

Change-Id: If6beff17ed3ddf85889aba5f41d1ba112cd74075
Signed-off-by: Jacob Garber <jgarber1@ualberta.ca>
Found-by: Coverity CID 1402160
Reviewed-on: https://review.coreboot.org/c/coreboot/+/34486
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: HAOUAS Elyes <ehaouas@noos.fr>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-by: Martin Roth <martinroth@google.com>

src/soc/intel/broadwell/minihd.c

@@ -64,7 +64,8 @@ static const u32 minihd_verb_table[] = {
 static void minihd_init(struct device *dev)
 {
 	struct resource *res;
-	u8 *base, reg32;
+	u8 *base;
+	u32 reg32;
 	int codec_mask, i;
 
 	/* Find base address */