There is currently an overlap where exchange IDs between what is used for
offloaded commands and by libfc for ELS commands.  Correct this so that
exchange ID range is:

Offloaded requests: 0 to 0xfff
libfc requests: 0x1000 to 0xfffe
Signed-off-by: Chad Dupuis <cdupuis@marvell.com>
Signed-off-by: Saurav Kashyap <skashyap@marvell.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>