cmd: spl: Fix compiling warning

Fix warning "cast from pointer to integer of different size".

Signed-off-by: York Sun <york.sun@nxp.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
diff --git a/cmd/spl.c b/cmd/spl.c
index ad03365..4d84492 100644
--- a/cmd/spl.c
+++ b/cmd/spl.c
@@ -109,12 +109,12 @@
 
 	c = find_cmd_tbl(argv[1], &cmd_spl_export_sub[0],
 		ARRAY_SIZE(cmd_spl_export_sub));
-	if ((c) && ((int)c->cmd <= SPL_EXPORT_LAST)) {
+	if ((c) && ((long)c->cmd <= SPL_EXPORT_LAST)) {
 		argc -= 2;
 		argv += 2;
-		if (call_bootm(argc, argv, subcmd_list[(int)c->cmd]))
+		if (call_bootm(argc, argv, subcmd_list[(long)c->cmd]))
 			return -1;
-		switch ((int)c->cmd) {
+		switch ((long)c->cmd) {
 #ifdef CONFIG_OF_LIBFDT
 		case SPL_EXPORT_FDT:
 			printf("Argument image is now in RAM: 0x%p\n",
@@ -153,7 +153,7 @@
 
 	c = find_cmd_tbl(argv[1], &cmd_spl_sub[0], ARRAY_SIZE(cmd_spl_sub));
 	if (c) {
-		cmd = (int)c->cmd;
+		cmd = (long)c->cmd;
 		switch (cmd) {
 		case SPL_EXPORT:
 			argc--;