qla2xxx: remove SGI SN2 support

The SGI SN2 support is about to be removed, so drop the bits specific to
it from this driver.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lkml.kernel.org/r/20190813072514.23299-13-hch@lst.de


Signed-off-by: Tony Luck <tony.luck@intel.com>