clk: zynqmp: Make zynqmp_clk_get_max_divisor static

Fix sparse warning:

drivers/clk/zynqmp/divider.c:259:5: warning:
 symbol 'zynqmp_clk_get_max_divisor' was not declared. Should it be static?
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Link: https://lkml.kernel.org/r/20200403083040.37748-1-yuehaibing@huawei.comReviewed-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

drivers/clk/zynqmp/divider.c

@@ -266,7 +266,7 @@ static const struct clk_ops zynqmp_clk_divider_ops = {
  * Return: Maximum divisor of a clock if query data is successful
  *	   U16_MAX in case of query data is not success
  */
-u32 zynqmp_clk_get_max_divisor(u32 clk_id, u32 type)
+static u32 zynqmp_clk_get_max_divisor(u32 clk_id, u32 type)
 {
 	const struct zynqmp_eemi_ops *eemi_ops = zynqmp_pm_get_eemi_ops();
 	struct zynqmp_pm_query_data qdata = {0};