Suppport for exposing hidden raid components
for sg interface. The sdev->no_uld_attach flag
will set set accordingly.

The sas module supports adding/removing raid
volumes using online storage management application
interface.

This patch rely's on patch's provided to me
by Christoph Hellwig, that exports device_reprobe.
I will post those patch's on behalf of Christoph.
Signed-off-by: Eric Moore <Eric.Moore@lsil.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>