IB/qib: Remove redundant assignment to ret

Variable 'ret' is set to zero but this value is never read as it is
overwritten with a new value later on, hence it is a redundant assignment
and can be removed.

Clean up the following clang-analyzer warning:

drivers/infiniband/hw/qib/qib_sd7220.c:690:2: warning: Value stored to
'ret' is never read [clang-analyzer-deadcode.DeadStores]

Link: https://lore.kernel.org/r/1619692940-104771-1-git-send-email-yang.lee@linux.alibaba.com
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Yang Li <yang.lee@linux.alibaba.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

drivers/infiniband/hw/qib/qib_sd7220.c

@@ -687,7 +687,6 @@ static int qib_sd7220_reg_mod(struct qib_devdata *dd, int sdnum, u32 loc,
 		spin_unlock_irqrestore(&dd->cspec->sdepb_lock, flags);
 		return -1;
 	}
-	ret = 0;
 	for (tries = EPB_TRANS_TRIES; tries; --tries) {
 		transval = qib_read_kreg32(dd, trans);
 		if (transval & EPB_TRANS_RDY)