arm64: dts: qcom: apq8096-db820c: drop unit address from PMI8994 regulator

The PMIC regulators are not supposed to have unit addresses.

Fixes: 2317b87a ("arm64: dts: qcom: db820c: Add vdd_gfx and tie it into mmcc")
Signed-off-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/20230312183622.460488-8-krzysztof.kozlowski@linaro.org