arch/tile: use #include <asm/atomic.h> in tilepro assembly files

arch/tile: use #include <asm/atomic.h> in tilepro assembly files

The standard <linux/atomic.h> is not safe to include from assembly, and
in general there's no need for it to be, since it's not very meaningful
for assembly code.

Assembly support in tilepro for atomics does need to get some constants
from the tilepro <asm/atomic.h>, however, so fix those files back to
the way they were, to directly #include <asm/atomic.h>.

Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>