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/silinux_ek874_defconfig b/configs/silinux_ek874_defconfig
index 894a996..5b01f1e 100644
--- a/configs/silinux_ek874_defconfig
+++ b/configs/silinux_ek874_defconfig
@@ -12,6 +12,7 @@
 CONFIG_SPL_TEXT_BASE=0xe6318000
 CONFIG_RCAR_GEN3=y
 CONFIG_TARGET_SILINUX_EK874=y
+CONFIG_REMAKE_ELF=y
 CONFIG_SYS_LOAD_ADDR=0x58000000
 CONFIG_FIT=y
 CONFIG_SUPPORT_RAW_INITRD=y