This reduces noise when kernel is compiled by newer GCC versions,
such as one used by external toolchain ports.
Reviewed by: kib, andrew(sys/arm and sys/arm64), emaste(partial), erj(partial)
Reviewed by: jhb (sys/dev/pci/* sys/kern/vfs_aio.c and sys/kern/kern_synch.c)
Differential Revision: https://reviews.freebsd.org/D10385
support frameworks(i.e. clk/reset/phy/tsensors/fuses...).
The framework is still far from perfect and probably doesn't have stable
interface yet, but we want to start testing it on more real boards and
different architectures.