spi_nxp_lpspi: Prevent edge case causing DMA error

Stop the transfer with error if at any point there is some
execution reached where transfer is being set up for 0 length, this can
cause problems where for example eDMA set up with this nonsense 0 length
channels can get an infinite error interrupt.

And this is probably an erroneously crafted transfer request anyways.

Signed-off-by: Declan Snyder <declan.snyder@nxp.com>