spi: davinci: Get rid of dangling variable

The previous commit left a variable unused, my bad.
Clean it up.

Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: David Lechner <david@lechnology.com>
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Fixes: 101a68e7 ("spi: davinci: Convert to use CS GPIO descriptors")
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Mark Brown <broonie@kernel.org>