MAINTAINERS: add missing clock driver coverage for Microchip FPGAs

MAINTAINERS: add missing clock driver coverage for Microchip FPGAs

When the CCC support was added, the clock binding coverage was
converted to a regex in commit 71c8517e004b ("MAINTAINERS: update
polarfire soc clock binding"), but the coverage for the clock drivers
themselves was not updated. Rectify that now.

Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20230222124610.257101-1-conor.dooley@microchip.com
Signed-off-by: Stephen Boyd <sboyd@kernel.org>