[POWERPC] macintosh: Replace deprecated __initcall with device_initcall

Signed-off-by: Robert P. J. Day <rpjday@crashcourse.ca>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>