arch/x86: Correctly determine number of enabled cores

Instead of using MAX of (cores_enabled, MAX_CPUS), use MIN
which is correct.

TEST=tested with dmidecode

Change-Id: Id0935f48e73c037bb7c0e1cf36f94d98a40a499c
Signed-off-by: Andrey Petrov <anpetrov@fb.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/36662
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: David Hendricks <david.hendricks@gmail.com>
Reviewed-by: Philipp Deppenwiese <zaolin.daisuki@gmail.com>
Reviewed-by: Nico Huber <nico.h@gmx.de>
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>

src/arch/x86/smbios.c

@@ -659,7 +659,7 @@ static int smbios_write_type4(unsigned long *current, int handle)
 	t->processor_type = 3; /* System Processor */
 	t->core_count = (res.ebx >> 16) & 0xff;
 	/* Assume we enable all the cores always, capped only by MAX_CPUS */
-	t->core_enabled = MAX(t->core_count, CONFIG_MAX_CPUS);
+	t->core_enabled = MIN(t->core_count, CONFIG_MAX_CPUS);
 	t->l1_cache_handle = 0xffff;
 	t->l2_cache_handle = 0xffff;
 	t->l3_cache_handle = 0xffff;