PicoBoot v0.4 CLKFIX Test

Test build of PicoBoot v0.4 with the FLASH SPI CLKDIV changed to 4 to help with rp2040 boards that have slower flash to improve boot reliability, along with gekkoboot built against Libogc2 commit fdb690015676f07ae3bccc59df5ac09b4fb2ce48 to improve SD card compatibility.

This build can also picoboot from IDE-EXI v2 in SLOTS A, B and SP1

picoboot_full.uf2 = the full picoboot build for original RP2040 boards

picoboot_full_zero.uf2 = full picoboot build for RP2040 Zero boards