x86/acpi: Fix Coverity issue CID 1399153

This patch fixes Coverity issue
CID 1399153: Uninitialized variables  (UNINIT)

Change-Id: I736b532c687612912271317b8941e69f41af00ba
Signed-off-by: Werner Zeh <werner.zeh@siemens.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/31782
Reviewed-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/src/arch/x86/acpi.c b/src/arch/x86/acpi.c
index 486f8e3..b51b5a6 100644
--- a/src/arch/x86/acpi.c
+++ b/src/arch/x86/acpi.c
@@ -150,7 +150,7 @@
 unsigned long acpi_create_madt_lapics(unsigned long current)
 {
 	struct device *cpu;
-	int index, apic_ids[CONFIG_MAX_CPUS], num_cpus = 0;
+	int index, apic_ids[CONFIG_MAX_CPUS] = {0}, num_cpus = 0;
 
 	for (cpu = all_devices; cpu; cpu = cpu->next) {
 		if ((cpu->path.type != DEVICE_PATH_APIC) ||