fs/binfmt_elf.c: use list_for_each_entry()

[adobriyan@gmail.com: fixup compilation]
  Link: http://lkml.kernel.org/r/20190205064334.GA2152@avx2
Link: http://lkml.kernel.org/r/20190204202800.GB27482@avx2


Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>