parisc: fix unwind with recent gcc versions

kernel unwinding is broken with gcc >= 4.x.  Part of the problem is that
binutils seems very sensitive to where the unwind information is stored.

Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Kyle McMartin <kyle@mcmartin.ca>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>