frv: drop _PAGE_FILE and pte_file()-related helpers

frv: drop _PAGE_FILE and pte_file()-related helpers

commit ca5bfa7b390017f053d7581bc701518b87bc3d43 upstream.

We've replaced remap_file_pages(2) implementation with emulation.  Nobody
creates non-linear mapping anymore.

This patch also increase number of bits availble for swap offset.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>