xilinx: zynq: Guard code around SPL_FS_LOAD_PAYLOAD_NAME

Guard code around CONFIG_SPL_FS_LOAD_PAYLOAD_NAME usage to avoid
compilation failure.

Signed-off-by: Michal Simek <michal.simek@amd.com>
Link: https://lore.kernel.org/r/f15a9762494945814b06a71db90ee4db59dd17ed.1738910601.git.michal.simek@amd.com
diff --git a/board/xilinx/zynq/board.c b/board/xilinx/zynq/board.c
index a852d5b..8dbfa56 100644
--- a/board/xilinx/zynq/board.c
+++ b/board/xilinx/zynq/board.c
@@ -179,6 +179,7 @@
 	memset(buf, 0, sizeof(buf));
 
 	switch ((zynq_slcr_get_boot_mode()) & ZYNQ_BM_MASK) {
+#if defined(CONFIG_SPL_FS_LOAD_PAYLOAD_NAME)
 	case ZYNQ_BM_SD:
 		snprintf(buf, DFU_ALT_BUF_LEN,
 			 "mmc 0=boot.bin fat 0 1;"
@@ -193,6 +194,7 @@
 			 CONFIG_SYS_SPI_U_BOOT_OFFS);
 		break;
 #endif
+#endif
 	default:
 		return;
 	}