[binutils-gdb] Remove unused function declarations in target.h

[sergiodj+buildbot@redhat.com]

*** TEST RESULTS FOR COMMIT b072f6c163b25ec90d592ca42aeb56bc88e8da0c ***

Author: Simon Marchi <simon.marchi@ericsson.com>
Branch: master
Commit: b072f6c163b25ec90d592ca42aeb56bc88e8da0c

Remove unused function declarations in target.h
find_default_create_inferior and find_default_attach were removed in b3ccfe11.

gdb/ChangeLog:

	* target.h (find_default_create_inferior): Remove declaration.
	(find_default_attach): Likewise.