arm64: dts: qcom: sc8280xp-pmics: fix sdam 'reg' property

The SPMI PMIC register region width is fixed and should not be encoded
in the devicetree.

Fixes: d6dbbda3 ("arm64: dts: qcom: sc8280xp-pmics: add pmk8280 sdam nvram")
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20230320135710.1989-3-johan+linaro@kernel.org