[POWERPC] spufs: Internal __spufs_get_foo() routines should take a spu_context *

The SPUFS attribute get routines take a void * because the generic attribute
code doesn't know what sort of data it's passing around.

However our internal __spufs_get_foo() routines can take a spu_context *
directly, which saves plonking it in and out of a void * again.

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Acked-by: Arnd Bergmann <arnd.bergmann@de.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>