[libc][math] Refactor bf16sub Math Functions to Header Only

[hulxv]

This is tracking issue to refactor bf16sub math functions currently implemented in LLVM libc to be header-only.

part of: #147386

Target Functions:

• bf16sub
• bf16subf
• bf16subf128

CC: @bassiounix

[llvmbot]

@llvm/issue-subscribers-libc

Author: Mohamed Emad (hulxv)

Details

This is tracking issue to refactor bf16sub math functions currently implemented in LLVM libc to be header-only.

part of: #147386

Target Functions:

• bf16sub
• bf16subf
• bf16subf128

CC: @bassiounix