USB: fix USB_OHCI_HCD_SSB dependencies

This patch fixes a bug introduced by
commit b22817b3.

Signed-off-by: Adrian Bunk <bunk@kernel.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Michael Buesch <mb@bu3sch.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>