[libc] Wrong guards for `totalorderbf16` and `totalordermagbf16` (#188241)
Currently the guards for `totalorderbf16` and `totalordermagbf16` are as
follows:
```
#ifndef LLVM_LIBC_SRC_MATH_TOTALORDERMAGF16_H
#define LLVM_LIBC_SRC_MATH_TOTALORDERMAGF16_H
-
#endif // LLVM_LIBC_SRC_MATH_TOTALORDERMAGF16_H
```
and
```
#ifndef LLVM_LIBC_SRC_MATH_TOTALORDERF16_H
#define LLVM_LIBC_SRC_MATH_TOTALORDERF16_H
-
#endif // LLVM_LIBC_SRC_MATH_TOTALORDERF16_H
```
As we can see these are for F16 and not BF16 .
This Pr intends to fix that with correct guards as `TOTALORDERBF16` and
`TOTALORDERMAGBF16`