ARM: 9190/1: kdump: add invalid input check for 'crashkernel=0'

Add invalid input check expression when 'crashkernel=0' is specified
running kdump.

Signed-off-by: Austin Kim <austindh.kim@gmail.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>

arch/arm/kernel/setup.c

@@ -1004,7 +1004,8 @@ static void __init reserve_crashkernel(void)
 	total_mem = get_total_mem();
 	ret = parse_crashkernel(boot_command_line, total_mem,
 				&crash_size, &crash_base);
-	if (ret)
+	/* invalid value specified or crashkernel=0 */
+	if (ret || !crash_size)
 		return;
 
 	if (crash_base <= 0) {