arm64: zynqmp: Fix return value of board_fit_config_name_match

Empty implementation should not return 0 (success) because that mean that
passed name matches the board configuration.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>

arch/arm/mach-zynqmp/spl.c

@@ -132,6 +132,6 @@ 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);
 
-	return 0;
+	return -1;
 }
 #endif