Add definition for te_fp8_fnuz when ROCm version is 6.2

[HollowMan6]

Description

Before ROCm/clr@353f15a (In ROCm6.2), FP8 OCP is not added and the code implementation is in FNUZ, so we define te_fp8_fnuz() to return true, to fix the following error:

transformer_engine/common/recipe/delayed_scaling.hip:42:14: error: use of undeclared identifier 'te_fp8_fnuz'
     42 |       return te_fp8_fnuz() ? 240 : 448;
        |              ^
  1 error generated when compiling for gfx90a.

Type of change

• Documentation change (change only to the documentation, either a fix or a new content)
• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Infra/Build change
• Code refactoring

Changes

• Define te_fp8_fnuz for ROCm 6.2

Checklist:

• I have read and followed the contributing guidelines
• The functionality is complete
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

[wenchenvincent]

Thanks for reporting the issue and submitting the PR. This issue has been fixed in #172. Thus closing this PR.