arm: spear: x600: Remove EFI support to reduce image size

EFI is not needed on x600. So lets remove the EFI support to make it fit
into the 0x60000 image size limit again.
Signed-off-by: NStefan Roese <sr@denx.de>

configs/x600_defconfig

@@ -22,3 +22,4 @@ CONFIG_NETDEVICES=y
 CONFIG_ETH_DESIGNWARE=y
 CONFIG_USE_TINY_PRINTF=y
 CONFIG_OF_LIBFDT=y
+# CONFIG_EFI_LOADER is not set