arm64: dts: qcom: pm8998: adjust coincell node name to bindings

The spmi-pmic bindings say that pm8941-coincell should be called
'charger'.

Reviewed-by: Konrad Dybcio <konrad.dybcio@somainline.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Luca Weiss <luca@z3ntu.xyz>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20221031175119.939860-3-luca@z3ntu.xyz