[PATCH] SH: atomic.h fixes

[Roland McGrath]

Your current version looks like it still evaluates the macro arg VALUE twice
in several macros.  Also, I am not sure about using __typeof(value).
Stick to __typeof(*(mem)) (and don't forget the parens around the macro arg),
since the value might be a widened literal or something.

I don't know SH at all, but I don't see anything that looks like system
calls in here so I am confused by your comments.