m68knommu: use generic find_next_bit_le()

The implementation of find_next_bit_le() on m68knommu is identical with
the generic implementation of find_next_bit_le().

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Greg Ungerer <gerg@uclinux.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>