mfd: qcom-spmi-pmic: Add pm8953 compatible

Document the compatible for pm8953 as found in msm8953.

Signed-off-by: Luca Weiss <luca@z3ntu.xyz>
Acked-by: Konrad Dybcio <konrad.dybcio@somainline.org>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20220112194118.178026-5-luca@z3ntu.xyz