spi: butterfly: Fix checkpatch issue

Fix the following checkpatch errors and warnings.

  ERROR: space required before the open brace '{'
  ERROR: space required after that close brace '}'
  ERROR: space required before the open parenthesis '('
  ERROR: do not use C99 // comments
  WARNING: sizeof *pp should be sizeof(*pp)

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