spi: cadence-quadspi: Enable SPI_TX_QUAD

Enable the SPI_TX_QUAD mode bit in the host->mode_bits to support
data transmission over four lines to improve the performance.

Tested the functionality on AM62Lx EVM (W25N01JW) in 1S-4S-4S mode.

Signed-off-by: Santhosh Kumar K <s-k6@ti.com>
Link: https://patch.msgid.link/20250102120544.1407152-1-s-k6@ti.com


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