ARM: S3C2443: Accommodate cpufreq frequency scheme in armdiv

Cpufreq uses frequencies in kHz and not Hz, so set_rate and round_rate
would be called with a frequency of 266666000 instead of 266666666 but
the clock functions check for rates smaller or equal to the targetrate.

As the armdiv does not support steps this small we can accommodate
this by simply also setting the last 3 digits of the calculated rate
to zero.

Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>