Fixing bsr64 for MathLib

[kuqin12]

Preface

Please ensure you have read the contribution docs prior
to submitting the pull request. In particular,
pull request guidelines.

Description

When using GCC(-like) compilers to build MathLib, the sqrt_d function will use built-in functions for bit scan reverse. However, the calculation for 64 bit BSR is incorrectly using the built-in function specifically for unsigned long, which is 32-bit for CLANGPDB and cause the unit test to fail.

This change fixed the built-in function usage.

For each item, place an "x" in between [ and ] if true. Example: [x].
(you can also check items in the GitHub UI)

• Impacts functionality?
  • Functionality - Does the change ultimately impact how firmware functions?
  • Examples: Add a new library, publish a new PPI, update an algorithm, ...
• Impacts security?
  • Security - Does the change have a direct security impact on an application,
    flow, or firmware?
  • Examples: Crypto algorithm change, buffer overflow fix, parameter
    validation improvement, ...
• Breaking change?
  • Breaking change - Will anyone consuming this change experience a break
    in build or boot behavior?
  • Examples: Add a new library class, move a module to a different repo, call
    a function in a new library class in a pre-existing module, ...
• Includes tests?
  • Tests - Does the change include any explicit test code?
  • Examples: Unit tests, integration tests, robot tests, ...
• Includes documentation?
  • Documentation - Does the change contain explicit documentation additions
    outside direct code modifications (and comments)?
  • Examples: Update readme file, add feature readme file, link to documentation
    on an a separate Web page, ...

How This Was Tested

Unit test passed on QEMU SBSA platform built with CLANGPDB.

Integration Instructions

N/A

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 10.86%. Comparing base (3709a53) to head (99befa5).
Report is 1 commits behind head on release/202311.

Additional details and impacted files

@@               Coverage Diff               @@
##           release/202311     #492   +/-   ##
===============================================
  Coverage           10.86%   10.86%           
===============================================
  Files                 142      142           
  Lines               22379    22379           
  Branches             1808     1808           
===============================================
  Hits                 2431     2431           
  Misses              19916    19916           
  Partials               32       32           

Flag	Coverage Δ
MsCorePkg	1.43% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.