Before, we use "arm_freq" in command line to set 1.2G. Now we will read the
fuse bit and "arm_freq", get the mini value to be used as "arm_max_freq".And:
1. you can easily set CPU max freq on what frequency you want by cmdline.
2. if you didn't set arm_freq in cmdline, kernel will read the fuse bit
(0x021bc440) to set the right arm_max_freq.

At the same time, add 1Ghz setpoint if chip max freq is 1.2Ghz.

Signed-off-by: Robin Gong <b38343@freescale.com>