Chip-select and SPI initialization uses the new config, whereas the drivers
still use the existing defines.
The configuration in board_config.h can be removed after all drivers are
updated.
- reduces amount of board configuration required
- removes the cyclic dependency between io_timers_t and timer_io_channels_t
Fixes a bug in the fmuk66-v3 config: the 2. timer has 3 channels associated
not 2.
Fixes a bug in the modelai config: the 2. timer has 4 channels associated.
Daniel Agar