mm: remove ptep_test_and_clear_dirty and ptep_clear_flush_dirty

Nobody is using ptep_test_and_clear_dirty and ptep_clear_flush_dirty.  Remove
the functions from all architectures.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>