Fix bfd/dwarf2.c build breakage

Fix bfd/dwarf2.c build breakage

Fix build breakage introduced by commit 089e3718bd8d ("Greatly improve
the speed if looking up DWARF line number information."):

 -  bfd_boolean is_linkage;
 -  const char *name;
 -  struct arange arange;
 +  int                  line;
 +  int                  tag;
 +  bfd                  boolean is_linkage;

bfd/ChangeLog:
2016-11-08  Pedro Alves  <palves@redhat.com>

	* dwarf2.c (struct funcinfo) <is_linkage>: Type is bfd_boolean,
	not "bfd boolean".