anv/xe: improve error handling for the vm_bind ioctl

This MR is the result of a long conversation I had with @thomash regarding vm_bind error handling. We can do better under memory pressure situations, so that's what the series tries to do.

It was also agreed that xe.ko would slightly improve error reporting for the vm_bind ioctl, so the last patch addresses that. Given the nature of the change, it should be possible to merge our side even before xe.ko merges its change. Still, it would be nice to receive a ping from @thomash when it happens.

Cc: @zehortigoza our xe.ko backend specialist.