I tried compiling a PPC32 kernel with PREEMPT + SMP and it failed
because we didn't have a _raw_write_trylock.  This patch adds
_raw_write_trylock, moves the exports of _raw_*lock from
arch/ppc/kernel/ppc_ksyms.c to arch/ppc/lib/locks.c, and makes
__spin_trylock static since it is only used in locks.c.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>