clk: export fixed-factor, gate & mux registration

These registration calls may be used by loadable modules. Export them.

Signed-off-by: Mike Turquette <mturquette@linaro.org>

diff --cc drivers/clk/clk-fixed-factor.c
Simple merge

diff --cc drivers/clk/clk-gate.c
Simple merge

diff --cc drivers/clk/clk-mux.c
Simple merge