spi: spi-mem: Extend spi_mem_adjust_op_size() to honor max xfer size

spi: spi-mem: Extend spi_mem_adjust_op_size() to honor max xfer size

Extend spi_mem_adjust_op_size() to take spi->max_write_size and
spi->max_read_size into account.

Signed-off-by: Vignesh R <[email protected]>
Tested-by: Simon Goldschmidt <[email protected]>
Tested-by: Stefan Roese <[email protected]>
Tested-by: Horatiu Vultur <[email protected]>
Reviewed-by: Jagan Teki <[email protected]>
Tested-by: Jagan Teki <[email protected]> #zynq-microzed