MAINTAINERS: Promote Krzysztof to PCI controller maintainer

Krzysztof has contributed significantly to the PCI controller subsystem
recently through reviews, tooling and submissions.

Update the MAINTAINERS file to grant him the role he deserves.

Link: https://lore.kernel.org/r/20230130100850.24994-1-lpieralisi@kernel.org
Signed-off-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Krzysztof Wilczyński <kw@linux.com>