MAINTAINERS: Include PCI bindings in host bridge entry

Almost all PCI bindings are controller bindings, so list them under the
PCI native host bridge and endpoint entry.

Link: https://lore.kernel.org/r/20221116215337.1032890-1-robh@kernel.org
Signed-off-by: Rob Herring <robh@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Lorenzo Pieralisi <lpieralisi@kernel.org>