build system: break overly long lines into logical units

Change-Id: I37b716acb305a79614cea184f57b8488111eab7a
Signed-off-by: Patrick Georgi <pgeorgi@chromium.org>
Reviewed-on: https://review.coreboot.org/12540
Tested-by: build bot (Jenkins)
Reviewed-by: Martin Roth <martinroth@google.com>
1 file changed