plat/marvell/armada: cleanup MSS SRAM if used for copy

This patch cleans up the MSS SRAM if it was used for MSS image
copy (secure boot mode).

Change-Id: I23f600b512050f75e63d59541b9c21cef21ed313
Signed-off-by: Konstantin Porotchkin <kostap@marvell.com>
Reviewed-on: https://sj1git1.cavium.com/c/IP/SW/boot/atf/+/30099

Reviewed-by: Stefan Chulski <stefanc@marvell.com>
Tested-by: sa_ip-sw-jenkins <sa_ip-sw-jenkins@marvell.com>

plat/marvell/armada/common/mss/mss_scp_bootloader.c

@@ -161,6 +161,11 @@ static int mss_image_load(uint32_t src_addr, uint32_t size,
 
 	bl2_plat_configure_mss_windows(mss_regs);
 
+	/* Wipe the MSS SRAM after using it as copy buffer */
+	if (sram) {
+		memset((void *)sram, 0, MSS_SRAM_SIZE);
+	}
+
 	/* Release M3 from reset */
 	mmio_write_32(MSS_M3_RSTCR(mss_regs),
 		     (MSS_M3_RSTCR_RST_OFF << MSS_M3_RSTCR_RST_OFFSET));