build system: drop generic util/ %.c -> %.o rule

It shouldn't be necessary because tools should give their own rules.

Change-Id: I8654afaf4f64a14a73677d9901562f7d962f0404
Signed-off-by: Patrick Georgi <patrick@georgi-clan.de>
Reviewed-on: http://review.coreboot.org/10290
Tested-by: build bot (Jenkins)
Reviewed-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
1 file changed