spi: cadence: fix static checker warning

commit b41da35403e4ee7f37e9f6a3fa77615b2a1b48e3 from
git@git.assembla.com:cavium/WindRiver.linux.git

This patch fixes Smatch static checker warning.
CDNS_XSPI_CMD_REG_5 is used in ACMD mode and currently
only STIG mode is enabled which doesn't use CDNS_XSPI_CMD_REG_5
and hence everything was working in STIG mode.
Since plan is to use same function cdns_xspi_trigger_command()
in ACMD mode, increasing size of the array passed to it.

Fixes: a16cc807

 ("spi: cadence: add support for Cadence XSPI controller")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Link: https://lore.kernel.org/linux-spi/20210930134231.GA14363@kili/
Signed-off-by: Parshuram Thombare <pthombar@cadence.com>
Link: https://lore.kernel.org/r/1633336704-22735-1-git-send-email-pthombar@cadence.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Witold Sadowski <wsadowski@marvell.com>
Change-Id: Id7d9ed467cf02fdc8e57da3843e88ad5e9310cc8
Reviewed-on: https://sj1git1.cavium.com/c/IP/SW/kernel/linux/+/67404
Reviewed-by: Chandrakala Chavva <cchavva@marvell.com>
Tested-by: Sunil Kovvuri Goutham <sgoutham@marvell.com>
Signed-off-by: Ruiqiang Hao <Ruiqiang.Hao@windriver.com>