spi: bitbang: Fix checkpatch issue

Fix the following checkpatch warnings

  WARNING: sizeof *cs should be sizeof(*cs)
  WARNING: please, no space before tabs
  WARNING: space prohibited between function name and open parenthesis '('
  WARNING: line over 80 characters

Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Mark Brown <broonie@linaro.org>