clk: fixed_rate: add API for directly registering fixed rate clocks

Current driver only supports registering fixed rate clocks from DT. Add
new API which makes it possible to register fixed rate clocks directly
from e.g. platform specific clock drivers.

Reviewed-by: Peng Fan <peng.fan@nxp.com>
Signed-off-by: Tero Kristo <t-kristo@ti.com>
Signed-off-by: Tero Kristo <kristo@kernel.org>
diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h
index 6fda14f..9d296f2 100644
--- a/include/linux/clk-provider.h
+++ b/include/linux/clk-provider.h
@@ -247,6 +247,9 @@
 		void __iomem *reg, u8 shift, u8 width,
 		u8 clk_mux_flags);
 
+struct clk *clk_register_fixed_rate(struct device *dev, const char *name,
+				    ulong rate);
+
 const char *clk_hw_get_name(const struct clk *hw);
 ulong clk_generic_get_rate(struct clk *clk);