sh: add sh7724 kick callback to clk_div4_table

This patch adds a ->kick() callback to clk_div4_table
and ties it into sh_clk_div4_set_rate(). A sh7724
specific kick function is also added that updates the
KICK bit whenever div4 clocks in FRQCRA and FRQCRB
have been set. Allows us to set the VPU clock.

Signed-off-by: Magnus Damm <damm@opensource.se>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>