msm: pm8921-charger: increase the warm threshold temperature

The JEITA specification mandates that the charge voltage and current be
reduced at warmer temperatures. However it does not necessarily specify
the exact warm temperature.

The recommendation for the hardware is to use 45degC as the warm
threshold instead of 40degC.

Change-Id: I4971d605c3475949be64372dc6bd3355ed258527
Signed-off-by: Abhijeet Dharmapurikar <adharmap@codeaurora.org>