For `.reloc` directive, if the relocation offset is a symbol, then the relocation entry should be placed into relocation section and its `sh_info` should point to the section where relocation offset symbol at.
Test case:
.text
ret
nop
nop
.reloc foo, R_RISCV_32, 6
.data
.globl foo
foo:
.word 0
.word 0
.word 0
```
The relocation entry should be placed into `.reloc.data`. And it is also what gnu `as` does.