Revert D103717 "[InstrProfiling] Make __profd_ unconditionally private for ELF"

This reverts commit 76d0747e.

If a group has `__llvm_prf_vals` due to static value profiler counters
(`NS!=0`), we cannot make `__llvm_prf_data` private, because a prevailing text
section may reference `__llvm_prf_data` and will cause a `relocation refers to a
discarded section` linker error.

Note: while a `__profc_` group is non-prevailing, it may be referenced by a
prevailing text section due to inlining.

```
group section [   66] `.group' [__profc__ZN5clang20EmitClangDeclContextERN4llvm12RecordKeeperERNS0_11raw_ostreamE] contains 4 sections:
   [Index]    Name
   [   67]   __llvm_prf_cnts
   [   68]   __llvm_prf_vals
   [   69]   __llvm_prf_data
   [   70]   .rela__llvm_prf_data
```