soc/intel/braswell: Make `num_cpus` unsigned

Change-Id: Iff6da3dc9c744a3dae3f4dd4ac37a91f348450a3
Signed-off-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/58915
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Felix Held <felix-coreboot@felixheld.de>

src/soc/intel/braswell/include/soc/pattrs.h

@@ -29,7 +29,7 @@ struct pattrs {
 	int stepping;
 	const void *microcode_patch;
 	int address_bits;
-	int num_cpus;
+	unsigned int num_cpus;
 	unsigned int bclk_khz;
 };