Blackfin: SMP: rename the arch_xxx lock funcs to __raw_xxx

The external functions are named __raw_xxx, not arch_xxx, so rename the
prototypes to match reality.  This fixes some simple build errors in the
bfin_ksyms.c code which exports these helpers to modules.

Signed-off-by: Graf Yang <graf.yang@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>