RDMA/bnxt_re: Remove a redundant 'memset'

'wqe' is already zeroed at the top of the 'while' loop, just a few lines
below, and is not used outside of the loop.

So there is no need to zero it again, or for the variable to be declared
outside the loop.

Link: https://lore.kernel.org/r/20200308065442.5415-1-christophe.jaillet@wanadoo.fr
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>