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_n5x_defconfig b/configs/socfpga_n5x_defconfig
index 6bef8c5..7e7d1cc 100644
--- a/configs/socfpga_n5x_defconfig
+++ b/configs/socfpga_n5x_defconfig
@@ -13,6 +13,7 @@
 CONFIG_IDENT_STRING="socfpga_n5x"
 CONFIG_SPL_FS_FAT=y
 # CONFIG_PSCI_RESET is not set
+CONFIG_REMAKE_ELF=y
 CONFIG_BOOTDELAY=5
 CONFIG_USE_BOOTARGS=y
 CONFIG_BOOTARGS="earlycon panic=-1 earlyprintk=ttyS0,115200"