Commit 99cbd064 ("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: NArnd Bergmann <arnd@arndb.de>
Cc: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: NMike Turquette <mturquette@linaro.org>