clk: export __clk_round_rate for providers

Commit 99cbd064b0 ("clk: qcom: Support display RCG clocks") adds
a use of the __clk_round_rate in a clock provided that can be built
as a loadable module.

This exports the symbol to avoid the build error from compiling
the qcom clock as a module.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index 2df2b26..8b73ede 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -1006,6 +1006,7 @@
 	else
 		return clk->rate;
 }
+EXPORT_SYMBOL_GPL(__clk_round_rate);
 
 /**
  * clk_round_rate - round the given rate for a clk