ARM: imx: Enable LTO for Data Modul i.MX8M Mini eDM SBC

Enable LTO to reduce the size of SPL.

Signed-off-by: Marek Vasut <marex@denx.de>
diff --git a/configs/imx8mm_data_modul_edm_sbc_defconfig b/configs/imx8mm_data_modul_edm_sbc_defconfig
index 3ccd268..d982188 100644
--- a/configs/imx8mm_data_modul_edm_sbc_defconfig
+++ b/configs/imx8mm_data_modul_edm_sbc_defconfig
@@ -24,6 +24,7 @@
 CONFIG_ENV_OFFSET_REDUND=0xFFFC0000
 CONFIG_IMX_BOOTAUX=y
 CONFIG_SYS_LOAD_ADDR=0x60000000
+CONFIG_LTO=y
 CONFIG_ENV_VARS_UBOOT_CONFIG=y
 CONFIG_SYS_MONITOR_LEN=1048576
 CONFIG_FIT=y