spi: Fixes for v3.15 A few driver specific fixes here: - SH HSPI was dealing with its clocks incorrectly which meant it didn't work on some SoCs, fixing this also requires a small fix to one of the SoC clock trees to avoid breaking existing users. - The SiRF driver appears to have had several quality problems, it's fairly new and not widely used so this isn't too worrying. - A brute force fix for excessive locking in the Atmel driver, it needs further investigation but this deals with the immediate issue. - A build fix for the Blackfin driver.