Stop using the pico BSP, just the raw HAL.

Hopefully this might make it easier to change the HAL for the RP2350 one.

Author: thejpster

Cargo.lock

@@ -10,14 +10,8 @@ version = "0.7.0"
 [dependencies]
 # Useful Cortex-M specific functions (e.g. SysTick)
 cortex-m = "0.7"
-# The Raspberry Pi Pico BSP
-rp-pico = { version = "0.9", default-features = false, features = [
-    "rt",
-    "critical-section-impl",
-    "rom-func-cache"
-] }
 # The Raspberry Pi RP2040 HAL (so we can turn defmt on)
-rp2040-hal = { version = "0.10", features = [ "defmt" ] }
+rp2040-hal = { version = "0.10", features = [ "defmt", "rt", "critical-section-impl", "rom-func-cache" ] }
 # Cortex-M run-time (or start-up) code
 cortex-m-rt = "0.7"
 # The BIOS to OS API