package/binutils: fix XTENSA_NDIFF handling for PR ld/25861

Fix for xtensa PR ld/25861 introduced a regression in handling negative
symbol differences resulting in linker performing incorrect relaxation
or failing to link. Fix XTENSA_NDIFF relocation handling.

Backported from:
https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;a=commitdiff;h=d548f47df4d2e3d117d504a4c9977982c78a0556



Fixes: f0291ef4 ("package/binutils: fix xtensa PR ld/25861")
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Tested-by: Romain Naour <romain.naour@gmail.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>