spi: pl022: Fix trailing whitespace

Fix checkpatch error:

  ERROR: trailing whitespace
  #1198: FILE: spi-pl022.c:1198:
Signed-off-by: Jay Fang <f.fangjian@huawei.com>
Link: https://lore.kernel.org/r/1616566602-13894-12-git-send-email-f.fangjian@huawei.comSigned-off-by: Mark Brown <broonie@kernel.org>