ENGR00173857 MX6Q: add 600M work point

ENGR00173857 MX6Q: add 600M work point

Add a 600M work point for better suit for cpufreq driver.

For current MX6Q clock tree, the most near 600M working point
is 624M, so we use 624M as 600M working point.

We found we have 200/400/800/1G working point is not very
good for cpufreq adjustment, since we don't have a uniform
working point distribution, since the interactive governor
is using cpu usage to adjust frequency, eg, 60% CPU, going
to 600M working point, if above a threshold (%85 default)
will going to max frequency directly.

From the [sheet] , you can see in game case, it will have much
chance in 400M working point, between 400M and 800M working
point, there is a gap, so the 400M will be most used frequency.
we add 600 WP to fill this gap, and make game case have
better experience.

[sheet] http://wiki.freescale.net/download/attachments/
40052424/Compare.xlsx?version=1&modificationDate=1326086907000

Wiki About this:
http://wiki.freescale.net/display/MADAndroid
/i.MX6Q+Performance+and+Power+Optimization

Signed-off-by: Zhang Jiejing <jiejing.zhang@freescale.com>