spi: sirf: Add missing spi_master_{resume,suspend} calls to PM callbacks

This is required since commit 2025172e

 "spi/bitbang: Use core message pump".
spi-bitbang now uses core message pump, so it needs to call spi_master_suspend/
spi_master_resume to stop/start the queue while suspend/resume.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Mark Brown <broonie@linaro.org>