cmd_fuse: return CMD_RET_FAILURE on error

Fuse drivers, like the mxs_ocotp.c, may return negative error codes but
the commands are only allowed to return CMD_RET_* enum values to the
shell, otherwise the following error appears:

	"exit not allowed from main input shell."

Signed-off-by: Hector Palacios <hector.palacios@digi.com>
Reviewed-by: Benoît Thébaudeau <benoit.thebaudeau.dev@gmail.com>
diff --git a/common/cmd_fuse.c b/common/cmd_fuse.c
index abab978..d4bc0f6 100644
--- a/common/cmd_fuse.c
+++ b/common/cmd_fuse.c
@@ -128,7 +128,7 @@
 
 err:
 	puts("ERROR\n");
-	return ret;
+	return CMD_RET_FAILURE;
 }
 
 U_BOOT_CMD(