mm, meminit: remove early_page_nid_uninitialised

The helper early_page_nid_uninitialised() has been dead since commit
974a786e ("mm, page_alloc: remove MIGRATE_RESERVE") so remove the
dead code.

Link: http://lkml.kernel.org/r/1468008031-3848-2-git-send-email-mgorman@techsingularity.net


Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>