[SCSI] qla2xxx: Fix "active_mask" may be used uninitialized warning.

Since active_mask is first assigned in an "else" block, the compiler throws
a warning saying that the active_mask variable may be used uninitialized in
a print statement later.  Initialize active_mask to 0 in the declaration to
stop the warning.

Signed-off-by: Chad Dupuis <chad.dupuis@qlogic.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>