misc: vexpress: Off by one in vexpress_syscfg_exec()

BugLink: https://bugs.launchpad.net/bugs/1818813

commit f8a70d8b upstream.

The > comparison should be >= to prevent reading beyond the end of the
func->template[] array.

(The func->template array is allocated in vexpress_syscfg_regmap_init()
and it has func->num_templates elements.)

Fixes: 974cc7b9 ("mfd: vexpress: Define the device as MFD cells")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Juerg Haefliger <juergh@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

drivers/misc/vexpress-syscfg.c

@@ -61,7 +61,7 @@ static int vexpress_syscfg_exec(struct vexpress_syscfg_func *func,
 	int tries;
 	long timeout;
 
-	if (WARN_ON(index > func->num_templates))
+	if (WARN_ON(index >= func->num_templates))
 		return -EINVAL;
 
 	command = readl(syscfg->base + SYS_CFGCTRL);