plat-mxc: cpufreq.c: revert delay to original state.
ENGR00241003-1 mx6: need to add delay in LDO voltage setting

1.LDO ramp up time may be modified by ROM code
according to fuse setting, cpu freq driver use
fixed delay time which assume the LDO ramp up time
is the reset value of ANATOP register, need to set
it to reset value in regulator init.

2.The regulator set voltage should take care of
the ramp up time, calculate the ramp up time based
of register setting and to the delay, make sure that
when the set voltage function return, the voltage is
stable enough.

3.CPUFreq no need to use delay, it is already taken
care by regulator voltage setting.

Signed-off-by: Anson Huang <b20788@freescale.com>
ENGR00241003-2 pfuze: using _sel interface to add delay support

use regulator _sel interface set to support auto delay,
as when regulator's voltage go up, it will take some time
to ramp up to the required voltage, so the delay is necessary.
_sel interface set support such function, now we switch to this
interface set.

Signed-off-by: Anson Huang <b20788@freescale.com>