MAINTAINERS: Add Manivannan Sadhasivam as Reviewer for PCI native host bridge and endpoint drivers

I've been reviewing the native host bridge drivers for some time and would
like to be listed as a Reviewer formally.

Link: https://lore.kernel.org/r/20240812055707.6778-1-manivannan.sadhasivam@linaro.org
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

Author: Mani-Sadhasivam

MAINTAINERS

@@ -17616,6 +17616,7 @@ F:	drivers/pci/controller/pci-xgene-msi.c
 PCI NATIVE HOST BRIDGE AND ENDPOINT DRIVERS
 M:	Lorenzo Pieralisi <lpieralisi@kernel.org>
 M:	Krzysztof Wilczyński <kw@linux.com>
+R:	Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
 R:	Rob Herring <robh@kernel.org>
 L:	linux-pci@vger.kernel.org
 S:	Supported