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/socfpga_agilex_atf_defconfig b/configs/socfpga_agilex_atf_defconfig
index 2d342c9..f85953f 100644
--- a/configs/socfpga_agilex_atf_defconfig
+++ b/configs/socfpga_agilex_atf_defconfig
@@ -13,6 +13,7 @@
 CONFIG_TARGET_SOCFPGA_AGILEX_SOCDK=y
 CONFIG_IDENT_STRING="socfpga_agilex"
 CONFIG_SPL_FS_FAT=y
+CONFIG_REMAKE_ELF=y
 CONFIG_SYS_LOAD_ADDR=0x02000000
 CONFIG_FIT=y
 CONFIG_SPL_FIT_SIGNATURE=y