spi: Fixes for v3.15 A few core fixes around outlying cases here, nothing that should affect most users but useful fixes. The diffstat is rather larger than one might hope due some simple code motion in the fix for !CONFIG_DMA, the actual meaningful change is much smaller. - Fix handling of unsupported dual and quad mode support on slave registration so that drivers that can degrade gracefully do so, preventing regressions for drivers this is added. - Fix build in !CONFIG_DMA cases following addition of generic DMA mapping support. - Fix error handling for queue creation which due to wider kernel changes can be triggered more easily. - A couple of driver specific fixes.