scsi: qedi: Remove comparison of u16 idx with zero.

Variable idx is defined as u16 thus statement (idx < 0) is always false
and should be removed.

Signed-off-by: Christos Gkekas <chris.gekas@gmail.com>
Acked-by: Manish Rangankar <Manish.Rangankar@cavium.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>