[binutils-gdb] Don't forward declare enum target_hw_bp_type

[sergiodj+buildbot@redhat.com]

*** TEST RESULTS FOR COMMIT 2f56f7c302c8d4012cc47d8bd261b151b2ddfa22 ***

Author: Pedro Alves <palves@redhat.com>
Branch: master
Commit: 2f56f7c302c8d4012cc47d8bd261b151b2ddfa22

Don't forward declare enum target_hw_bp_type
Can't do that in C++.

2015-02-27  Pedro Alves  <palves@redhat.com>

	* nat/x86-dregs.h (enum target_hw_bp_type): Remove forward
	declaration.
	Include break-common.h.