drivers: memc: update interface of memc flexspi driver for multi device

Update interface of memc flexspi driver to better handle multiple
devices. Previously, using multiple devices on one FlexSPI bus would
require the user to configure each device to install its command table
(referred to as a LUT table by the driver) at an offset, so that it did
not overlap with other devices on the bus.

This commit changes the interface of the memc flexspi driver to instead
configure the LUT and flash device in one call. This allows the memc
driver to record the port each LUT sequence is used with, so that
future FlexSPI transfer requests can have their LUT offsets adjusted
based on the target port (which will correspond to a target device)

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