ARM: dts: msm: Update the bcl thresholds for SDM670

Update the thresholds for vbat for SDM670 based on latest
recommendation. The new thresholds are,
vbat = 3.2V
vbat_low = 2.8V
vbat_too_low = 2.6V

Change-Id: I2500620014e496d142c697b0c081c442470df824
Signed-off-by: Manaf Meethalavalappu Pallikunhi <manafm@codeaurora.org>