[SCSI] kill scsi host template suspend/resume

With libata converted to use sdev->manage_start_stop for suspend and
resume, sht->suspend/resume() has no user left and low level
suspend/ressume should be taken care of by low level driver's
suspend/resume callbacks (e.g. PCI or PCMCIA driver callbacks).  This
patch removes sht->suspend/resume() callbacks.

This change is suggested by Christoph Hellwig.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>