[Bug #193] fix fp8 blockwise real quantization

[meenchen]

What does this PR do?

Type of change: bug fix

Overview: instead of using amax, we should compute block_scale on the fly

Usage

# Add a code snippet demonstrating how to use this

Testing

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Additional Information

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 73.52%. Comparing base (32d168c) to head (17dcf35).
⚠️ Report is 56 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #522      +/-   ##
==========================================
+ Coverage   73.38%   73.52%   +0.14%     
==========================================
  Files         180      181       +1     
  Lines       17934    18207     +273     
==========================================
+ Hits        13160    13387     +227     
- Misses       4774     4820      +46     

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