clk: gpio: Really allow an optional clock= DT property

We mis-merged the original patch from Russell here and so the
patch went almost all the way, except that we still failed to
probe when there wasn't a clocks property in the DT node. Allow
that case by making a negative value from
of_clk_get_parent_count() into "no parents", like the original
patch did.

Fixes: 7ed88aa2 ("clk: fix clk-gpio.c with optional clock= DT property")
Cc: Russell King <rmk+kernel@arm.linux.org.uk>
Cc: Michael Turquette <mturquette@baylibre.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>

drivers/clk/clk-gpio.c

@@ -289,7 +289,7 @@ static void __init of_gpio_clk_setup(struct device_node *node,
 
 	num_parents = of_clk_get_parent_count(node);
 	if (num_parents < 0)
-		return;
+		num_parents = 0;
 
 	data = kzalloc(sizeof(*data), GFP_KERNEL);
 	if (!data)