[mips32][pic32mx][hal] get rid of bogus DRIVER_EXT_FIELDS
[mips32][pic32mx][gpt] more robust way for polled delay
[mips32][pic32mx][pal] update documentation accordingly to the implementation
[mips32][pic32mx] export frequency of peripheral bus clock
[mips32][pic32mx][gpt] do not enable interrupt if callback is not specified
[hal][eic] pass IRQ number to the handler
[hal][pwm] extend API with pwmChannelChangeWidth
[mips32][pic32mx] PWM LLD