dt-bindings: PCI: qcom: Update maintainers entry

Stan is no longer working with MMSOL and expressed his interest to not
continue maintaining Qcom PCIe driver. Since I took over the driver
maintainership, I'm stepping in to maintain the binding also.

Link: https://lore.kernel.org/r/20230308082424.140224-2-manivannan.sadhasivam@linaro.org


Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>