SDK 2.3.0 risc-v extensions detection

[shtirlic]

In this commit b9e3417
we now have tests for compressed extensions zca_zcb_zcmp
But commenting # set(PICO_COMPILER pico_riscv_gcc_zcb_zcmp ) produces ASM without cm. instructions

Using https://github.com/xpack-dev-tools/riscv-none-elf-gcc-xpack/releases/tag/v15.2.0-1 as toolchain

set(PICO_BOARD pico2)
set(PICO_PLATFORM rp2350-riscv)
set(PICO_USE_STACK_GUARDS ON)
# set(PICO_DEOPTIMIZED_DEBUG ON)
# set(PICO_COMPILER pico_riscv_gcc_zcb_zcmp )
# set(PICO_GCC_TRIPLE "riscv-none-elf")
set(PICO_TOOLCHAIN_PATH /opt/riscv/)

with

set(PICO_COMMON_LANG_FLAGS " -march=rv32ima_zicsr_zifencei_zba_zbb_zbs_zbkb_zca_zcb_zcmp  -mabi=ilp32")

I see the the cm.mva01s s1,s0 in dis file.

[lurch]

#3076 should fix this...