common: bootm: check return value of strict_strtoul

Before continue, check return value of strict_strtoul.

Signed-off-by: Peng Fan <Peng.Fan@freescale.com>
Cc: Albert Aribaud <albert.u.boot@aribaud.net>
Cc: Simon Glass <sjg@chromium.org>
Cc: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Joe Hershberger <joe.hershberger@ni.com>
Cc: Hans de Goede <hdegoede@redhat.com>
Cc: York Sun <yorksun@freescale.com>
Cc: Tom Rini <trini@konsulko.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

arch/arm/lib/bootm.c

@@ -290,7 +290,10 @@ static void boot_jump_linux(bootm_headers_t *images, int flag)
 
 	s = getenv("machid");
 	if (s) {
-		strict_strtoul(s, 16, &machid);
+		if (strict_strtoul(s, 16, &machid) < 0) {
+			debug("strict_strtoul failed!\n");
+			return;
+		}
 		printf("Using machid 0x%lx from environment\n", machid);
 	}