ARM: renesas: Enable LTO on R-Car3 Falcon

Enable LTO (link time optimization) to improve optimization
and reduce code size by cca. 30 kiB.

Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
diff --git a/configs/r8a779a0_falcon_defconfig b/configs/r8a779a0_falcon_defconfig
index 8cf2921..28fef6f 100644
--- a/configs/r8a779a0_falcon_defconfig
+++ b/configs/r8a779a0_falcon_defconfig
@@ -16,6 +16,7 @@
 # CONFIG_PSCI_RESET is not set
 CONFIG_ARMV8_PSCI=y
 CONFIG_SYS_LOAD_ADDR=0x58000000
+CONFIG_LTO=y
 CONFIG_REMAKE_ELF=y
 CONFIG_SYS_MONITOR_LEN=1048576
 CONFIG_FIT=y