RISC-V: drop SOC_MICROCHIP_POLARFIRE for ARCH_MICROCHIP

SOC_MICROCHIP_POLARFIRE doesn't have any remaining in-kernel users, so
time has come to remove it. Foolish auld me left the "POLARFIRE" in the
new, hidden, config option when I renamed it and changed all of the
users however. As HPSC has been announced, and is not a PolarFire,
drop mention of that specific FPGA family from the new user-visible
config option.
Acked-by: Palmer Dabbelt <palmer@rivosinc.com>
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>

arch/riscv/Kconfig.socs

 menu "SoC selection"
 
 config ARCH_MICROCHIP_POLARFIRE
-	def_bool SOC_MICROCHIP_POLARFIRE
+	def_bool ARCH_MICROCHIP
 
-config SOC_MICROCHIP_POLARFIRE
-	bool "Microchip PolarFire SoCs"
+config ARCH_MICROCHIP
+	bool "Microchip SoCs"
 	help
-	  This enables support for Microchip PolarFire SoC platforms.
+	  This enables support for Microchip SoC platforms.
 
 config ARCH_RENESAS
 	bool "Renesas RISC-V SoCs"

arch/riscv/configs/defconfig

@@ -25,7 +25,7 @@ CONFIG_BLK_DEV_INITRD=y
 CONFIG_EXPERT=y
 # CONFIG_SYSFS_SYSCALL is not set
 CONFIG_PROFILING=y
-CONFIG_SOC_MICROCHIP_POLARFIRE=y
+CONFIG_ARCH_MICROCHIP=y
 CONFIG_ARCH_RENESAS=y
 CONFIG_SOC_SIFIVE=y
 CONFIG_ARCH_SOPHGO=y