spi: spi-zynqmp-gqspi: Correct a couple of misspellings in kerneldoc

spi: spi-zynqmp-gqspi: Correct a couple of misspellings in kerneldoc

Fixes the following W=1 kernel build warning(s):

 drivers/spi/spi-zynqmp-gqspi.c:205: warning: Function parameter or member 'slavecs' not described in 'zynqmp_gqspi_selectslave'
 drivers/spi/spi-zynqmp-gqspi.c:205: warning: Function parameter or member 'slavebus' not described in 'zynqmp_gqspi_selectslave'
 drivers/spi/spi-zynqmp-gqspi.c:205: warning: Excess function parameter 'flashcs' description in 'zynqmp_gqspi_selectslave'
 drivers/spi/spi-zynqmp-gqspi.c:205: warning: Excess function parameter 'flashbus' description in 'zynqmp_gqspi_selectslave'
 drivers/spi/spi-zynqmp-gqspi.c:902: warning: Function parameter or member 'dev' not described in 'zynqmp_qspi_suspend'
 drivers/spi/spi-zynqmp-gqspi.c:902: warning: Excess function parameter '_dev' description in 'zynqmp_qspi_suspend'

Signed-off-by: Lee Jones <lee.jones@linaro.org>
Reviewed-by: Michal Simek <michal.simek@xilinx.com>
Link: https://lore.kernel.org/r/20200717135424.2442271-11-lee.jones@linaro.org
Signed-off-by: Mark Brown <broonie@kernel.org>