sh: fix CONFIG_SH_PCLK_FREQ bug for sh7724

CONFIG_SH_PCLK_FREQ=33333333 is correct for sh7724.
sh7724 master clock is 33333333, but peripheral is 41666666.
This bug came to light because sh-sci driver had changed clk
from "module_clk" to "peripheral_clk"

Signed-off-by: Kuninori Morimoto <morimoto.kuninori@renesas.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>