drivers: spi: nxp: fix PCS broken issue and PCS_HOLD_ON support

Different LPSPI IPs are used for RT11xx and MCXN. On a older version of
LPSPI, a transmit command or a TX data need to be issued to end a frame.
On a new version, no such requirement.

Based on above information, we have to make DMA transfers "cascade" in
the DMA ISR to keep CS asserted during the whole SPI transfer.

PCS_HOLD_ON is a feature to keep CS asserted during multi SPI transfers.
It is implemented and supported on new LPSPI IP but it is impossible to
be supported on an older version like RT11xx.

Signed-off-by: Raymond Lei <raymond.lei@nxp.com>