drivers: dma: mcux_mcux_lpc: support hardware triggering

The LPC DMA IP offers hardware triggering via a series of SOC-specific
signals, often including sources like GPIO pins or hardware timers.
Support hardware triggers via the "dma_slot" field of the DMA
configuration structure. Currently support is offered for setting the
following:
- Trigger polarity
- Trigger level/edge mode
- burst mode
- burst length
- peripheral request

Signed-off-by: Daniel DeGrasse <daniel.degrasse@nxp.com>