drivers/infiniband/ulp/srpt/ib_srpt.c: fix build with gcc-4.4.4

gcc-4.4.4 has issues with initialization of anonymous unions:

drivers/infiniband/ulp/srpt/ib_srpt.c: In function 'srpt_zerolength_write':
drivers/infiniband/ulp/srpt/ib_srpt.c:854: error: unknown field 'wr_cqe' specified in initializer
drivers/infiniband/ulp/srpt/ib_srpt.c:854: warning: initialization makes integer from pointer without a cast

Work aound this.

Fixes: 2a78cb4d ("IB/srpt: Fix an out-of-bounds stack access in srpt_zerolength_write()")
Cc: Bart Van Assche <bart.vanassche@wdc.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Jason Gunthorpe <jgg@mellanox.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>