spi: microchip-core-qspi: Add support for microchip fpga qspi controllers

Add a driver for Microchip FPGA QSPI controllers. This driver also
supports "hard" QSPI controllers on Polarfire SoC.

Signed-off-by: Naga Sureshkumar Relli <nagasuresh.relli@microchip.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20220808064603.1174906-4-nagasuresh.relli@microchip.com
Signed-off-by: Mark Brown <broonie@kernel.org>