mmu: Simplify access_fault()

Spotted by Avi.

Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>
mmu: Simplify fault handler

Suggested by Avi.

Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>
mmu: Ditch find_vma()

Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>