using the linux-libre 4.15 kernel openrc gets stuck setting the system clock using the hardware clock

this problem was not present with kernel 4.14 and previous

affects:

* linux-libre 4.15.2_gnu-1
* linux-libre 4.15.9_gnu-2
* linux-libre 4.15.9_gnu-3
* linux-libre 4.16.7_gnu-1
* linux-libre 4.17.2_gnu-1