[SCSI] ibmvscsi: Enhanced error logging

Converts ibmvscsi to use dev_printk and friends to simplify
debugging. ibmvscsi adapter initialization now looks like this:

ibmvscsi 30000005: SRP_VERSION: 16.a
ibmvscsi 30000005: partner initialization complete
ibmvscsi 30000005: sent SRP login
ibmvscsi 30000005: SRP_LOGIN succeeded

Additionally, this patch adds the logging of a couple return codes in
a couple logs.

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