MAINTAINERS: generify the Microchip RISC-V entry name

These drivers work on our other FPGAs, for example the non-SoC PolarFire
connected to an FU-540 via chiplink. Make the entry a wee bit more
generic to match. While at it, remove the / from the heading so that it
matches other, neighbouring RISC-V entries.

Signed-off-by: Conor Dooley <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Arnd Bergmann <[email protected]>

Author: ConchuOD

MAINTAINERS

@@ -17725,7 +17725,7 @@ F:	arch/riscv/
 N:	riscv
 K:	riscv
 
-RISC-V/MICROCHIP POLARFIRE SOC SUPPORT
+RISC-V MICROCHIP FPGA SUPPORT
 M:	Conor Dooley <[email protected]>
 M:	Daire McNamara <[email protected]>
 L:	[email protected]