clk: remove exported function from __init section

The symbol of_fixed_clk_setup is exported and annotated __init.
This looks like section mismatch.
Fix this by removing the __init annotation of of_fixed_clk_setup.

Signed-off-by: Denis Efremov <yefremov.denis@gmail.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>