[SCSI] qla2xxx: Added support for quiescence mode for ISP82xx.

Support is added for quiescence mode. This feature is for P3P
adapters. Any of the functions can put the firmware into quiescence
state. All the others have to ack that request. During quiescence mode
current commands are processed and all the new incoming I/Os are
blocked. Loop resync is performed after firmware comes out of
quiescence state.

Signed-off-by: Saurav Kashyap <saurav.kashyap@qlogic.com>
Signed-off-by: Madhuranath Iyengar <Madhu.Iyengar@qlogic.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>