megasas: static SAS addresses

megasas: static SAS addresses

This patch introduces a new property 'sas_address' which
allows the user to specify the SAS address for the HBA.
The default address is following the NAA locally assigned
identifier format with the locally assigned address
0x525400 as used eg for the MAC addresses.
The lower bytes are set to the pci address which
will ensure uniqueness for the local machine.

The port addresses are now calculated based on the magic
number 0x1221 (which is found in real hardware, too) plus
the device number.

Signed-off-by: Hannes Reinecke <hare@suse.de>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Andreas Faerber <afaerber@suse.de>
Cc: Anthony Liguori <anthony@codemonkey.ws>
Cc: Alexander Graf <agraf@suse.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>