drivers: dma: introduce SMARTDMA dma driver

Introduce SMARTDMA dma driver. The SMARTDMA is a peripheral present on
some NXP SOCs, which implements a programmable DMA engine. The DMA
engine does not use channels, but rather provides a series of API
functions implemented by the firmware provided with MCUX SDK.

These API functions can be selected by the dma_config slot parameter. A
custom API is also provided to allow the user to install an alternate
firmware into the SMARTDMA.

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