dt-bindings: PCI: pci-ep: Update Maintainers

Kishon's TI email ID is not active anymore, so use his kernel.org ID.

Also, since I've been maintaining the PCI endpoint framework, I'm
willing to maintain the DT binding as well. So add myself as the
co-maintainer.

Link: https://lore.kernel.org/linux-pci/20240828-pci-qcom-hotplug-v4-3-263a385fbbcb@linaro.org


Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
[kwilczynski: commit log]
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Acked-by: Rob Herring (Arm) <robh@kernel.org>