package/binutils: fix xtensa PR ld/25861

Handle link-time relaxation of full 16-bit difference values correctly
in xtensa linker. This fixes the following kind of build errors:

.../five-point.cpp:338:(.debug_line+0x3b12):
       	dangerous relocation: overflow after relaxation

Backported from:
https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;a=commitdiff;h=30ce8e47fad9b057b6d7af9e1d43061126d34d20
Fixes:
http://autobuild.buildroot.net/results/67a5545779bbe8ca2b21da1f3ff2002053710ce1/
http://autobuild.buildroot.net/results/87f38998d2d60b6bce3128589973187ef9596e28/



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