Coprocessor warnings when building for RISCV

[lurch]

If I try building pico-examples for rp2350-riscv then I get this build warning:

[540/738] Linking CXX executable scanvideo/hscroll_dma_tiles/hscroll_dma_tiles.elf
WARNING: Instruction mrc 0, #7, r8, c7, c15, #0 is not supported by GPIO Coprocessor
WARNING: Instruction mrc 0, #7, r8, c7, c15, #0 is not supported by GPIO Coprocessor
WARNING: Instruction mrc 0, #7, r8, c7, c15, #0 is not supported by GPIO Coprocessor
[655/738] Linking CXX executable scanvideo/mario_tiles/mario_tiles.elf
WARNING: Instruction mrc 0, #7, r8, c7, c15, #0 is not supported by GPIO Coprocessor
WARNING: Instruction mrc 0, #7, r8, c7, c15, #0 is not supported by GPIO Coprocessor
WARNING: Instruction mrc 0, #7, r8, c7, c15, #0 is not supported by GPIO Coprocessor
[738/738] Linking CXX executable stdio/pio/stdio_pio.elf

(and I'm afraid I've got no idea what it means or how significant it is!)

[will-v-pi]

Those are warnings from picotool coprodis - looks like coprocessor dissassembly is running on Risc-V binaries, when it should only be running on RP2350 Arm binaries - I'll push a PR to the SDK to fix this, but you can ignore those warnings for now

[lurch]

I'll close this then, in light of raspberrypi/pico-sdk#1875 👍