spi: spi-mem: Send appropriate number of dummy cycles in transfer

commit  ac3f4b13dc90414fd96fce69daaa99cdec22505d from
https://github.com/Xilinx/linux-xlnx.git

 xlnx_rebase_v5.10

Driver was not sending the appropriate number of dummy cycles during
transfers, due to this failures were observed during read operation.
This patch updates the driver to send required number of dummy cycles.

Signed-off-by: Amit Kumar Mahapatra <amit.kumar-mahapatra@xilinx.com>
State: pending
Signed-off-by: Quanyang Wang <quanyang.wang@windriver.com>