Makefile.inc1: bump elf tool chain version check after PR 215350 fix

[rlibby]

Summary

This causes builds to use the in-tree libdwarf with the bug fix instead
of the host library.

Test Plan

Monitor amd64-gcc build on ci, which uses an 11.0 build environment.

[bdrewery]

We might want to keep the old comment too or someone might trim this away if GCC no longer has the problem, or they may try making the condition specific to GCC when it is also supporting <11 upgrades.

[rlibby]

bdrewery feedback: restore old comment

[markj]

LGTM