Drop the fifo_lvl_mask and rx_lvl_offset and switch to the new port
config data.

Advantages of the change:
- drop dependency on the OF alias ID.
- FIFO depth is inferred from the compatible. GS101 integrates 16 SPI
  IPs, all with 64 bytes FIFO depths.
- use full mask for SPI_STATUS.{RX, TX}_FIFO_LVL fields. Using partial
  masks is misleading and can hide problems of the driver logic.

S3C64XX_SPI_ST_TX_FIFO_RDY_V2 was defined based on the USI's
SPI_VERSION.USI_IP_VERSION register field, which has value 2 at reset.

MAX_SPI_PORTS is updated to reflect the maximum number of ports for the
rest of the compatibles.
Signed-off-by: Tudor Ambarus <tudor.ambarus@linaro.org>
Link: https://msgid.link/r/20240216070555.2483977-12-tudor.ambarus@linaro.orgSigned-off-by: Mark Brown <broonie@kernel.org>