sound/oss/sb_common.c: fix casting warning

sound/oss/sb_common.c: In function 'probe_sbmpu':
sound/oss/sb_common.c:1231: warning: cast to pointer from integer of different size

Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>