MAINTAINERS: add polarfire rng, pci and clock drivers

Hardware random, PCI and clock drivers for the PolarFire SoC have been
upstreamed but are not covered by the MAINTAINERS entry, so add them.
Daire is the author of the clock & PCI drivers, so add him as a
maintainer in place of Lewis.

Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Stephen Boyd <sboyd@kernel.org>
Link: https://lore.kernel.org/r/20220707142041.4096246-1-conor.dooley@microchip.com

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Signed-off-by: Arnd Bergmann <arnd@arndb.de>