RDMA/bnxt_re: Use common error handling code in bnxt_qplib_alloc_dpi_tbl()

Add a jump target so that a bit of exception handling can be better reused
at the end of this function.

Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Acked-by: Devesh Sharma <devesh.sharma@broadcom.com>
Acked-by: Jonathan Toppins <jtoppins@redhat.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>