arm64: dts: qcom: sm7225-fairphone-fp4: Add pm7250b PMIC

The PM7250B is primarily used for charger and fuel gauge on Fairphone 4
but also has some thermal zones that we can configure already.

Signed-off-by: Luca Weiss <luca.weiss@fairphone.com>
Reviewed-by: Konrad Dybcio <konrad.dybcio@somainline.org>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20220902111055.106814-3-luca.weiss@fairphone.com