spi: zynq_qspi: Add support for zynq_qspi_mem_exec_op

Add support_ops function zynq_qspi_mem_exec_op to check controller
supported operations by spi-mem framework. Current default support ops
function does not allow dummy buswidth no more than 1, unless we are
using buswidth is 4 for TX.

Signed-off-by: Ashok Reddy Soma <ashok.reddy.soma@xilinx.com>
Link: https://lore.kernel.org/r/1657893679-20039-4-git-send-email-ashok.reddy.soma@xilinx.com


Signed-off-by: Michal Simek <michal.simek@amd.com>