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 71c8517e ("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.comSigned-off-by: Stephen Boyd <sboyd@kernel.org>

MAINTAINERS

@@ -17989,7 +17989,7 @@ F:	Documentation/devicetree/bindings/spi/microchip,mpfs-spi.yaml
 F:	Documentation/devicetree/bindings/usb/microchip,mpfs-musb.yaml
 F:	arch/riscv/boot/dts/microchip/
 F:	drivers/char/hw_random/mpfs-rng.c
-F:	drivers/clk/microchip/clk-mpfs.c
+F:	drivers/clk/microchip/clk-mpfs*.c
 F:	drivers/i2c/busses/i2c-microchip-corei2c.c
 F:	drivers/mailbox/mailbox-mpfs.c
 F:	drivers/pci/controller/pcie-microchip-host.c