msm: krait-regulator: auto mode workarounds for pm8841

On pm8841 before enabling automode set the pwm current limit to
2Amps and reset it back to 3.5Amps after disabling automode.
This helps prevent overshoot when pfm-pwm switch happens while
running in auto mode.

Change-Id: I001c1aa649d7eed629e48cbb6d97194681e43d1b
Signed-off-by: Abhijeet Dharmapurikar <adharmap@codeaurora.org>