If the RP2040 is using the ring oscilator (ROSC) rather than the crystal
oscilator (XOSC) then flashing program will take much longer. As the XOSC is not
enabled at boot we should not assume it will be enabled before the debugger is
connected (or indeed at all), thus should use the longer timeout during load
commands.
Increasing spinner timeout to 500 means `tc_printf` is not called during
the `_flash_range_erase`. This is important as `_flash_range_erase` is
used when loading. This fixes the issue:
https://github.com/blacksphere/blackmagic/issues/875
Also adding spinner timeout counter to reduce bus traffic.
