clk: ti: Mark ti_clk_features static

This variable isn't exported outside of this file so mark it
static. Silences the following sparse warning:

drivers/clk/ti/clk.c:36:24: warning: symbol 'ti_clk_features' was not declared. Should it be static?
Acked-by: Tero Kristo <t-kristo@ti.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>

drivers/clk/ti/clk.c

@@ -32,7 +32,7 @@
 struct ti_clk_ll_ops *ti_clk_ll_ops;
 static struct device_node *clocks_node_ptr[CLK_MAX_MEMMAPS];
 
-struct ti_clk_features ti_clk_features;
+static struct ti_clk_features ti_clk_features;
 
 struct clk_iomap {
 	struct regmap *regmap;