benchdnn: doc: add newly add f8_e4m3 and f8_e5m2

[airMeng]

Description

F8_E4M3 and F8_E5M2 have been introduced into OneDNN but missed in benchdnn doc.

Fixes # (github issue)

Checklist

General

• Do all unit and benchdnn tests (make test and make test_benchdnn_*) pass locally for each commit?
• Have you formatted the code using clang-format?

Performance improvements

• Have you submitted performance data that demonstrates performance improvements?

New features

• Have you published an RFC for the new feature?
• Was the RFC approved?
• Have you added relevant tests?

Bug fixes

• Have you included information on how to reproduce the issue (either in a github issue or in this PR)?
• Have you added relevant regression tests?

RFC PR

• Does RFC document follow the template?
• Have you added a link to the rendered document?

[airMeng]

@dzarukin Could you give a review?