subsys/debug: remove `CONFIG_EXCEPTION_STACK_TRACE_SYMTAB`

Having `CONFIG_EXCEPTION_STACK_TRACE_SYMTAB` to select the
`CONFIG_SYMTAB` or to explicitly not print the symbol name
during exception stack unwind seems unnecessary, as the extra
code to print the symbol name is negligible when compared with
the symbol table, so just remove it.

Signed-off-by: Yong Cong Sin <ycsin@meta.com>
Signed-off-by: Yong Cong Sin <yongcong.sin@gmail.com>