Check if symbol is defined when converting mov to lea

Check if symbol is defined when converting mov to lea

We need to check if symbol is defined when converting mov to lea since
SYMBOL_REFERENCES_LOCAL may return true on hidden undefined symbols.

	* elf32-i386.c (elf_i386_convert_mov_to_lea): Check if symbol
	is defined.
	* elf64-x86-64.c (elf_x86_64_convert_mov_to_lea): Likewise.