spi: spi-zynqmp-gqspi: use wait_for_completion_timeout to make zynqmp_qspi_exec_op not interruptible

When Ctrl+C occurs during the process of zynqmp_qspi_exec_op, the function
wait_for_completion_interruptible_timeout will return a non-zero value
-ERESTARTSYS immediately. This will disrupt the SPI memory operation
because the data transmitting may begin before the command or address
transmitting completes. Use wait_for_completion_timeout to prevent
the process from being interruptible.

This patch fixes the error as below:
root@xilinx-zynqmp:~# flash_erase /dev/mtd3 0 0
Erasing 4 Kibyte @ 3d000 --  4 % complete
    (Press Ctrl+C)
[  169.581911] zynqmp-qspi ff0f0000.spi: Chip select timed out
[  170.585907] zynqmp-qspi ff0f0000.spi: Chip select timed out
[  171.589910] zynqmp-qspi ff0f0000.spi: Chip select timed out
[  172.593910] zynqmp-qspi ff0f0000.spi: Chip select timed out
[  173.597907] zynqmp-qspi ff0f0000.spi: Chip select timed out
[  173.603480] spi-nor spi0.0: Erase operation failed.
[  173.608368] spi-nor spi0.0: Attempted to modify a protected sector.

Fixes: 1c26372e ("spi: spi-zynqmp-gqspi: Update driver to use spi-mem framework")
Signed-off-by: Quanyang Wang <quanyang.wang@windriver.com>
Reviewed-by: Amit Kumar Mahapatra <amit.kumar-mahapatra@xilinx.com>
Link: https://lore.kernel.org/r/20210408040223.23134-2-quanyang.wang@windriver.comSigned-off-by: Mark Brown <broonie@kernel.org>