package/binutils: fix assertion in 2.29 xtensa ld

Section sorting code in xtensa ld was incorrectly cleaned up in release
2.29, resulting in the following assertion when --sort-section,alignment
option is used:

  BFD (GNU Binutils) 2.29 assertion fail elf32-xtensa.c:3965

Backport the fix that restores original section sorting.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>