fix: Update GPTQ example README.md for typo

[chichun-charlie-liu]

minor typo that messed up the tables, also update lm-eval flag autogptq=True to gptqmodel=True (both will work, but just to be consistent)

Checklist for passing CI/CD:

• All commits are signed showing "Signed-off-by: Name <email@domain.com>" with git commit -signoff or equivalent
• PR title and commit messages adhere to Conventional Commits
• Contribution is formatted with tox -e fix
• Contribution passes linting with tox -e lint
• Contribution passes spellcheck with tox -e spellcheck
• Contribution passes all unit tests with tox -e unit

Note: CI/CD performs unit tests on multiple versions of Python from a fresh install. There may be differences with your local environment and the test environment.

[tharapalanivel]

LGTM