Makefile: update clean-utils & distclean-utils

Distclean-utils target was missing a backslash at the end to continue on
the next line.

Change-Id: I2bddff342f9c0fcb27e9b40ac94377c60ba5b7fe
Signed-off-by: Martin Roth <martinroth@google.com>
Reviewed-on: https://review.coreboot.org/20494
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
1 file changed