bnx2x: Fix static checker warning regarding `txdata_ptr'

Incorrect checking of array instead of array contents in panic_dump
flow - results of commit e2611998 ("bnx2x: Safe bnx2x_panic_dump()").

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Yuval Mintz <Yuval.Mintz@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>