Link USB drivers later in the kernel

We want to link the "regular" SCSI drivers before the USB storage
driver, since historically we've always detected internal SCSI disks
before the external USB storage modules.

The link order matters for initcall ordering, and this got broken by
mistake by commit 7586269c

 which moved
the USB host controller PCI quirk handling around.

Signed-off-by: Linus Torvalds <torvalds@osdl.org>