addr2line vs. inlined C functions called from C++

In this case the inlined function doesn't have DW_AT_linkage_name in
.debug_info, but the language is C++ so find_nearest_line goes looking
in the symbol table.  Since the function is inlined the enclosing
non-inline function symbol is returned from _bfd_elf_find_function,
which is wrong.  This patch only uses a symbol if its address matches.

	PR binutils/19315
	* dwarf2.c (_bfd_elf_find_function): Return symbol matched.
	(_bfd_dwarf2_find_nearest_line): Check symbol returned above
	against dwarf range.
	* elf-bfd.h (_bfd_elf_find_function): Update prototype.