Correct SPL use of CMD_FRU

This converts 1 usage of this option to the non-SPL form, since there is
no SPL_CMD_FRU defined in Kconfig

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/board/xilinx/common/board.c b/board/xilinx/common/board.c
index e2c957f..3dea238 100644
--- a/board/xilinx/common/board.c
+++ b/board/xilinx/common/board.c
@@ -306,7 +306,7 @@
 
 	debug("%s: i2c memory detected: %s\n", __func__, name);
 
-	if (CONFIG_IS_ENABLED(CMD_FRU) && xilinx_detect_fru(buffer))
+	if (IS_ENABLED(CONFIG_CMD_FRU) && xilinx_detect_fru(buffer))
 		return xilinx_read_eeprom_fru(dev, name, desc);
 
 	if (xilinx_detect_legacy(buffer))