DESC
remap_file_pages protection support: s390 bits
EDESC
From: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390 memory management changes for remap-file-pages-prot patch:

- Add pgoff_prot_to_pte/pte_to_pgprot, remove pgoff_to_pte (required for
  'prot' parameteter in shared-writeable mappings).

- Handle VM_FAULT_SIGSEGV from handle_mm_fault in do_exception.
