sb1250-mac.c: De-typedef, de-volatile, de-etc...

 Remove typedefs, volatiles and convert kmalloc()/memset() pairs to
kcalloc().  Also reformat the surrounding clutter.
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: Jeff Garzik <jeff@garzik.org>