spi: zynqmp_gqspi: Fix write issue at low frequencies
With current implementation we are seeing write issues at low frequencies
below 15Mhz. Make below changes to fix the issue.
1. Remove dummy genfifo entry in zynqmp_qspi_chipselect() which was
incorrectly added in the past
2. Enable and poll for TX_FIFO_Empty after Tx data is filled in FIFO in
zynqmp_qspi_fill_tx_fifo().
Signed-off-by: Ashok Reddy Soma <ashok.reddy.soma@xilinx.com>
Link: https://lore.kernel.org/r/1634652780-21755-1-git-send-email-ashok.reddy.soma@xilinx.com
Signed-off-by: Michal Simek <michal.simek@xilinx.com>