hwdb_parser: make sure that our patterns match the full property

We would catch stuff like:
 ACCEL_MOUNT_MATRIX=0, -1, 0; -1, 0, 0; 0, 0.0., 0
but not
 ACCEL_MOUNT_MATRIX=0, -1, 0; -1, 0, 0; 0, 0, 0.0.
because the match would stop at the next-to-last char. Fix that
by requiring a line end.