[PATCH 4/4] MIPS: Provide actually relaxed MMIO accessors

Improve performance for the relevant systems and remove the DMA ordering barrier from `readX_relaxed' and `writeX_relaxed' MMIO accessors, where it is not needed according to our requirements[1]. For consistency make the same arrangement with low-level port I/O accessors, but do not actually

[PATCH 4/4] MIPS: Provide actually relaxed MMIO accessors

Improve performance for the relevant systems and remove the DMA ordering barrier from `readX_relaxed' and `writeX_relaxed' MMIO accessors, where it is not needed according to our requirements[1]. For consistency make the same arrangement with low-level port I/O accessors, but do not actually