clk: ti: Check kzalloc() for failures

smatch reports a failure to check kzalloc() here:

drivers/clk/ti/clk.c:232
omap2_clk_provider_init() error: potential null dereference 'io'.
(kzalloc returns null)

Check for an allocation failure and return -ENOMEM.
Acked-by: Tero Kristo <t-kristo@ti.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>

drivers/clk/ti/clk.c

@@ -227,6 +227,8 @@ int __init omap2_clk_provider_init(struct device_node *parent, int index,
 	clocks_node_ptr[index] = clocks;
 
 	io = kzalloc(sizeof(*io), GFP_KERNEL);
+	if (!io)
+		return -ENOMEM;
 
 	io->regmap = syscon;
 	io->mem = mem;