amd/common/psp: Convert structure init to C99

Use C99 designated initializers for the psp_notify_dram() buffer
structure.

Change-Id: I2e18b3a2c19b8fb17d0f654b16def52517538957
Signed-off-by: Marshall Dawson <marshalldawson3rd@gmail.com>
Reviewed-on: https://review.coreboot.org/22847
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
diff --git a/src/soc/amd/common/block/psp/psp.c b/src/soc/amd/common/block/psp/psp.c
index b13aa57..bb0a5fe 100644
--- a/src/soc/amd/common/block/psp/psp.c
+++ b/src/soc/amd/common/block/psp/psp.c
@@ -161,14 +161,15 @@
  */
 int psp_notify_dram(void)
 {
-	struct mbox_default_buffer buffer;
 	int cmd_status;
+	struct mbox_default_buffer buffer = {
+		.header = {
+			.size = sizeof(buffer)
+		}
+	};
 
 	printk(BIOS_DEBUG, "PSP: Notify that DRAM is available... ");
 
-	buffer.header.size = sizeof(struct mbox_default_buffer);
-	buffer.header.status = 0; /* PSP does not report status for this cmd */
-
 	cmd_status = send_psp_command(MBOX_BIOS_CMD_DRAM_INFO, &buffer);
 
 	/* buffer's status shouldn't change but report it if it does */