spi: cadence-quadspi: Add QSPI support for Intel LGM SoC

Add QSPI controller support for Intel LGM SoC.

Signed-off-by: Ramuthevar Vadivel Murugan <vadivel.muruganx.ramuthevar@linux.intel.com>
Link: https://lore.kernel.org/r/20201124041840.31066-2-vadivel.muruganx.ramuthevar@linux.intel.com


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