Input: fix double equality sign in uevent

Looking at the uevent stream for input devices, all properties are on
the form "A=B" except the bitmap values, which are on the form
"A==B". This bug has been around at least since 2007, and the input
uevent code has been untouched since. The recent addition of device
properties suggests this is a good time for a remedy.
Acked-by: Dmitry Torokhov <dtor@mail.ru>
Signed-off-by: Henrik Rydberg <rydberg@euromail.se>

drivers/input/input.c

@@ -1473,7 +1473,7 @@ static int input_add_uevent_bm_var(struct kobj_uevent_env *env,
 {
 	int len;
 
-	if (add_uevent_var(env, "%s=", name))
+	if (add_uevent_var(env, "%s", name))
 		return -ENOMEM;
 
 	len = input_print_bitmap(&env->buf[env->buflen - 1],