[binutils-gdb] Remove unneeded explicit .o targets

[sergiodj+buildbot at sergiodj dot net]

*** TEST RESULTS FOR COMMIT 3322c5d9a102f9af099bd87cc65a1e2a70f91c78 ***

Author: Tom Tromey <tom@tromey.com>
Branch: master
Commit: 3322c5d9a102f9af099bd87cc65a1e2a70f91c78

Remove unneeded explicit .o targets

Makefile.in had special cases to compile printcmd.o and target-float.o
with a different set of warnings.  However, this is no longer
required, so this patch removes those rules.

gdb/ChangeLog
2018-09-04  Tom Tromey  <tom@tromey.com>

	* Makefile.in (printcmd.o, target-float.o): Remove.
	(GDB_WARN_CFLAGS_NO_FORMAT): Remove.