IB/hfi1: Notify remove MMU/RB callback of calling context

Tell the remove MMU/RB callback if it's being called as
part of a memory invalidation or not. This can be important
in preventing a deadlock if the remove callback attempts to
take the map_sem semaphore because the kernel's MMU
invalidation functions have already taken it.

Reviewed-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Reviewed-by: Dean Luick <dean.luick@intel.com>
Signed-off-by: Mitko Haralanov <mitko.haralanov@intel.com>
Signed-off-by: Jubin John <jubin.john@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>