soc/mediatek/mt8192/spm.c: Add missing <string.h>

Change-Id: I56a4e0fb42c881026f4ee1abe30f9b356af6a68f
Signed-off-by: Elyes HAOUAS <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/50168
Reviewed-by: Raul Rangel <rrangel@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/soc/mediatek/mt8192/spm.c

@@ -1,13 +1,13 @@
 /* SPDX-License-Identifier: GPL-2.0-only */
 
 #include <assert.h>
-#include <cbfs.h>
 #include <console/console.h>
 #include <delay.h>
 #include <device/mmio.h>
 #include <soc/mcu_common.h>
 #include <soc/spm.h>
 #include <soc/symbols.h>
+#include <string.h>
 #include <timer.h>
 
 #define SPM_SYSTEM_BASE_OFFSET	0x40000000