fix buglet in nto-procfs.c

fix buglet in nto-procfs.c

I happened to notice that nto-procfs.c defines
procfs_remove_hw_breakpoint but never uses it.  This caused it not to
be updated by my target-method-updating script.  This patch fixes the
function and installs it properly.  I have no way to test this,
however.

2014-02-19  Tom Tromey  <tromey@redhat.com>

	* nto-procfs.c (procfs_remove_hw_breakpoint): Add 'self'
	argument.
	(init_procfs_ops): Correctly set to_remove_hw_breakpoint.