Blackfin: cpufreq: fix dpm_state_table

This patch fixes an assumption that cclk's initial divisor will always be 1 (or
0 in the register).  TSCALE is always initialized on startup with a value of 4
regardless of the inital cclk divisor; so, we can't make the assumption without
making lots of other assumptions.  The TPERIOD value is set with a value of the
current cclk (value / (HZ * TSCALE)) - 1; so, we need to adjust based on this
initial frequency and not use cclk's initial divisor for adjusting the tscale.

Signed-off-by: Steven Miao <realmz6@gmail.com>
Signed-off-by: Bob Liu <lliubbo@gmail.com>