rewrite: Add USB patches from wii-linux-ngx

TESTERS: please try this kernel! Please try as many weird and wonderful combinations of USB as you like and post your results. Watch out for #14, and report related issues there. Please also try to use USB Mass Storage devices (flash drives, hard disks) when the system is low on RAM.

This pulls in the good ol' Mystery Patches, specifically this commit with some modifications to apply correctly to 4.19. This also tries to get around the USB DMA restrictions by assigning it coherent areas. I have no idea if this will work correctly, but hey; it's better than praying!