spi: sirf: fix line over 80 characters style issue

fix a lot of "line over 80 characters" checkpatch issues, on which
the users of the driver, key customers care about this very much.

Signed-off-by: Qipan Li <Qipan.Li@csr.com>
Signed-off-by: Barry Song <Baohua.Song@csr.com>
Signed-off-by: Mark Brown <broonie@linaro.org>