Convert CONFIG_REMAKE_ELF to Kconfig

This converts the following to Kconfig:
   CONFIG_REMAKE_ELF

Signed-off-by: Alper Nebi Yasak <alpernebiyasak@gmail.com>
diff --git a/configs/rcar3_salvator-x_defconfig b/configs/rcar3_salvator-x_defconfig
index 499e56e..f60ddf0 100644
--- a/configs/rcar3_salvator-x_defconfig
+++ b/configs/rcar3_salvator-x_defconfig
@@ -9,6 +9,7 @@
 CONFIG_SPL_TEXT_BASE=0xe6338000
 CONFIG_RCAR_GEN3=y
 CONFIG_TARGET_SALVATOR_X=y
+CONFIG_REMAKE_ELF=y
 CONFIG_SYS_LOAD_ADDR=0x58000000
 CONFIG_FIT=y
 CONFIG_SUPPORT_RAW_INITRD=y