cpu/x86/smm/smm_module_loaderv2.c: Use more variables

Reusing the 'size' variable for a different purpose later on in the
function makes the code harder to read.

Change-Id: Iceb10aa40ad473b41b7da0310554725585e3c2c2
Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/47070
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: David Hendricks <david.hendricks@gmail.com>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
diff --git a/src/cpu/x86/smm/smm_module_loaderv2.c b/src/cpu/x86/smm/smm_module_loaderv2.c
index 3fa5871..4bc385f 100644
--- a/src/cpu/x86/smm/smm_module_loaderv2.c
+++ b/src/cpu/x86/smm/smm_module_loaderv2.c
@@ -413,12 +413,14 @@
 	 * for default handler, but for relocated handler it lives at the beginning
 	 * of SMRAM which is TSEG base
 	 */
-	size = params->num_concurrent_stacks * params->per_cpu_stack_size;
-	stacks_top = smm_stub_place_stacks((char *)params->smram_start, size, params);
+	const size_t total_stack_size = params->num_concurrent_stacks *
+		params->per_cpu_stack_size;
+	stacks_top = smm_stub_place_stacks((char *)params->smram_start, total_stack_size,
+					   params);
 	if (stacks_top == NULL) {
 		printk(BIOS_ERR, "%s: not enough space for stacks\n", __func__);
 		printk(BIOS_ERR, "%s: ....need -> %p : available -> %zx\n", __func__,
-			base, size);
+			base, total_stack_size);
 		return -1;
 	}
 	params->stack_top = stacks_top;