Add mpfs-hal references to docs

Author: AlexCharlton

docs/pages/hal.adoc

@@ -12,3 +12,5 @@ async traits in `embedded-hal` and `embedded-hal-async`. You can also use these
 For the ESP32 series, there is an link:https://github.com/esp-rs/esp-hal[esp-hal] which you can use.
 
 For the WCH 32-bit RISC-V series, there is an link:https://github.com/ch32-rs/ch32-hal[ch32-hal], which you can use.
+
+For the Microchip PolarFire SoC, there is link:https://github.com/AlexCharlton/mpfs-hal[mpfs-hal].

docs/pages/overview.adoc

@@ -31,6 +31,7 @@ The Embassy project maintains HALs for select hardware, but you can still use HA
 * link:https://docs.embassy.dev/embassy-rp/[embassy-rp], for the Raspberry Pi RP2040 microcontroller.
 * link:https://github.com/esp-rs[esp-rs], for the Espressif Systems ESP32 series of chips.
 * link:https://github.com/ch32-rs/ch32-hal[ch32-hal], for the WCH 32-bit RISC-V(CH32V) series of chips.
+* link:https://github.com/AlexCharlton/mpfs-hal[mpfs-hal], for the Microchip PolarFire SoC.
 
 NOTE: A common question is if one can use the Embassy HALs standalone. Yes, it is possible! There are no dependency on the executor within the HALs. You can even use them without async,
 as they implement both the link:https://github.com/rust-embedded/embedded-hal[Embedded HAL] blocking and async traits.