[SCSI] ibmvscsi: Misc. locking fixes

Fix a couple locking bugs discovered during code inspection.
ibmvscsi_send_srp_event needs to be called with the host lock
held. This patch fixes a couple paths in the code where this
wasn't true.

Signed-off-by: Brian King <brking@linux.vnet.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>