powerpc/ps3: ps3_repository_read_mm_info() takes u64 * arguments

Fixes compiler warnings:

arch/powerpc/platforms/ps3/mm.c:1205: warning: passing argument 2 of 'ps3_repository_read_mm_info' from incompatible pointer type
arch/powerpc/platforms/ps3/mm.c:1205: warning: passing argument 3 of 'ps3_repository_read_mm_info' from incompatible pointer type

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Acked-by: Geoff Levand <geoffrey.levand@am.sony.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>