drivers: spi_mcux_lpspi: Added DMA support to NXP LPSPI driver

Adds DMA support to NXP's LPSPI driver. This can be enabled by selecting
the KConfig symbol CONFIG_SPI_MCUX_LPSPI_DMA, and requires the LPSPI
instances enabled in the devicetree to have valid DMA instances
assigned.

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