armv8: layerscape: fix SPL multi DTB loading

Mark board_fit_config_name_match() as weak so a board can overwrite the
empty function.
Signed-off-by: NMichael Walle <michael@walle.cc>
Reviewed-by: NPriyanka Jain <priyanka.jain@nxp.com>

arch/arm/cpu/armv8/fsl-layerscape/spl.c

@@ -129,7 +129,7 @@ int spl_start_uboot(void)
 }
 #endif	/* CONFIG_SPL_OS_BOOT */
 #ifdef CONFIG_SPL_LOAD_FIT
-int board_fit_config_name_match(const char *name)
+__weak int board_fit_config_name_match(const char *name)
 {
 	/* Just empty function now - can't decide what to choose */
 	debug("%s: %s\n", __func__, name);