extcon: Return error code on failure

Function get_zeroed_page() returns a NULL pointer if there is no enough
memory. In function extcon_sync(), it returns 0 if the call to
get_zeroed_page() fails. The return value 0 indicates success in the
context, which is incosistent with the execution status. This patch
fixes the bug by returning -ENOMEM.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=188611

Signed-off-by: Pan Bian <[e-mail]>
Signed-off-by: Chanwoo Choi <[e-mail]>

drivers/extcon/extcon.c

···
 		dev_err(&edev->dev, "out of memory in extcon_set_state\n");
 		kobject_uevent(&edev->dev.kobj, KOBJ_CHANGE);
 
-		return 0;
+		return -ENOMEM;
 	}
 
 	length = name_show(&edev->dev, NULL, prop_buf);