ARM: dts: qcom: pm8226: fix regulators node name

Adjust the node name to match bindings and fix the validation warning.

Reviewed-by: Konrad Dybcio <konrad.dybcio@somainline.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Signed-off-by: Luca Weiss <luca@z3ntu.xyz>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20221031175119.939860-1-luca@z3ntu.xyz