LoongArch: Use more appropriate assertions for the relocation of TLS LE

LoongArch: Use more appropriate assertions for the relocation of TLS LE

PR ld/33427

Patches introduced in the GCC mainline:

commit 8cad8f94b450be9b73d07bdeef7fa1778d3f2b96
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Fri Sep 5 15:40:51 2025 -0700

    c: Update TLS model after processing a TLS variable

    Set a tentative TLS model in grokvardecl and update TLS mode with
    the default TLS access model after a TLS variable has been fully
    processed if the default TLS access model is stronger,

triggered a linker error when building glibc using build-many-glibcs.py.

See: https://sourceware.org/pipermail/binutils/2025-September/144225.html

This fix uses more appropriate assertions.