Speed up the display of unwind tables by using a binary chop search to locate functio...

Speed up the display of unwind tables by using a binary chop search to locate function symbols.

	* readelf.c (find_symbol_for_address): Use a binary search to
	speed up symbol location.  Skip check for function symbol type.
	(*_unw_aux_info): Add funtab and nfuns fields contains a sorted
	list of function symbols.
	(dump_ia64_unwind): Initialise the funtab and nfuns fields and
	pass them to find_symbol_for_address.
	(dump_hppa_unwind): Likewise.
	(arm_print_vma_and_name): Pass funtab to find_symbol_for_address.
	(dump_arm_unwind): Initialise the funtab and nfuns fields.