parisc: Use generic extable search and sort routines

Switch to the generic extable search and sort routines which were introduced
with commit a272858 from Ard Biesheuvel. This saves quite some memory in the
vmlinux binary with the 64bit kernel.

Signed-off-by: Helge Deller <deller@gmx.de>
(cherry picked from commit 0de798584bdedfdad19db21e3c7aec84f252f4f3)
Signed-off-by: Alex Shi <alex.shi@linaro.org>