libvhost-user: Speedup gpa_to_mem_region() and vu_gpa_to_va()

libvhost-user: Speedup gpa_to_mem_region() and vu_gpa_to_va()

Let's speed up GPA to memory region / virtual address lookup. Store the
memory regions ordered by guest physical addresses, and use binary
search for address translation, as well as when adding/removing memory
regions.

Most importantly, this will speed up GPA->VA address translation when we
have many memslots.

Reviewed-by: Raphael Norwitz <raphael@enfabrica.net>
Acked-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20240214151701.29906-11-david@redhat.com>
Tested-by: Mario Casquero <mcasquer@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>