spi: nxp-flexspi: Fix ARCH_LAYERSCAPE dependency

Currently the NXP Flex SPI driver has a dependency on ARCH_LAYERSCAPE ||
HAS_IOMEM which means that the dependency is almost always true and the
driver available. Really these should be two separate dependencies, with
an || COMPILE_TEST dependency for the architecture to ensure build coverage
is maintained.

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20230221-spi-arch-deps-v1-3-83d1566474cf@kernel.org


Signed-off-by: Mark Brown <broonie@kernel.org>