Since the address of the new context is known before _NewContext() is invoked
(due to it being passed a properly aligned stack), there is no longer any
need for _NewContext to return the pointer to the context.
Furthermore, as a direct result of the properly aligned stack, the pointer to
the new context does not need to be passed as a separate parameter since it
will always match the passed stack pointer.
Change-Id: Ie57a9c4ad17f6f13e8b3f659cd701d4f8950ea97
Signed-off-by: Peter Mitsis <peter.mitsis@windriver.com>