MAINTAINERS: adjust file entry in RISC-V MICROCHIP SUPPORT

Commit 71c814e ("spi: microchip: rename driver file and internal
identifiers") renames spi-microchip-core.c to spi-mpfs.c, but misses to
adjust the file entry in RISC-V MICROCHIP SUPPORT.

Adjust the file entry after this renaming.

Signed-off-by: Lukas Bulwahn <lukas.bulwahn@redhat.com>
Link: https://patch.msgid.link/20251117104044.291517-1-lukas.bulwahn@redhat.com
Signed-off-by: Mark Brown <broonie@kernel.org>

Author: bulwahn

MAINTAINERS

@@ -22137,7 +22137,7 @@ F:	drivers/reset/reset-mpfs.c
 F:	drivers/rtc/rtc-mpfs.c
 F:	drivers/soc/microchip/mpfs-sys-controller.c
 F:	drivers/spi/spi-microchip-core-qspi.c
-F:	drivers/spi/spi-microchip-core.c
+F:	drivers/spi/spi-mpfs.c
 F:	drivers/usb/musb/mpfs.c
 F:	include/soc/microchip/mpfs.h