Most of the warnings emitted (we fail arch/sparc file
builds with -Werror) were legitimate but harmless, however
one case (n2_pcr_write) was a genuine bug.

Based almost entirely upon a patch by Sam Ravnborg.
Reported-by: NDennis Gilmore <dennis@ausil.us>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>