[SCSI] qla2xxx: Re-organized BSG interface specific code.

1. Segregate BSG interface specific code to new files.
2. Handle multiple vendor specific commands indepedently.
3. Reorganised support for reset, management and update FCoE firmware commands.
4. Fixed memory leak issue in Loopback.
5. Added new vendor command to support iiDMA using BSG interface.
6. Proper cleanup of dma mapped and dma allocated buffers for BSG request.

[jejb: fix up conflict and merge in Jiri Slaby lock imbalance patch]
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Harish Zunjarrao <harish.zunjarrao@qlogic.com>
Signed-off-by: Giridhar Malavali <giridhar.malavali@qlogic.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>