Fix reinoud-ification.

My odroid-xu has console again.
Updates for active and inactive release branches,
from PR 49127 by J. Lewis Muir.
-Wno-unused-const-variable for radeon kv_dpm.c.
Spell -Wno-missing-prototypes correctly.
We don't use radeon_(un)register_atpx_handler at the moment.
rv770_dpm.c needs -Wno-missing-field-initializers.
Disable maximum frequency setting for exynos5

While here add more known frequency settings for exynos4. They are currently
disabled since derived clocks are not adjusted.
Add KPLL for Exynos5 and EPLL is called DPLL on the 5410 :-/
Add KPLL
Ensure correctness of bus_dmamap_sync operations. Shouldn't affect RPI.