clk: st: Include clk.h

This clock provider uses the consumer API, so include clk.h
explicitly.

Cc: Gabriel Fernandez <gabriel.fernandez@st.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>

drivers/clk/st/clkgen-pll.c

@@ -16,6 +16,7 @@
 
 #include <linux/slab.h>
 #include <linux/of_address.h>
+#include <linux/clk.h>
 #include <linux/clk-provider.h>
 
 #include "clkgen.h"