spi: sirf: cleanup the indentation of marcos

let "#define" statement keep same indentation. the old code layout is
pretty ugly.
Signed-off-by: NQipan Li <Qipan.Li@csr.com>
Signed-off-by: NBarry Song <Baohua.Song@csr.com>
Signed-off-by: NMark Brown <broonie@kernel.org>