bnxt_en: Fix possible memory leak in bnxt_rdma_aux_device_init()

If ulp = kzalloc() fails, the allocated edev will leak because it is
not properly assigned and the cleanup path will not be able to free it.
Fix it by assigning it properly immediately after allocation.

Fixes: 30343221 ("bnxt_en: Remove runtime interrupt vector allocation")
Reviewed-by: Andy Gospodarek <andrew.gospodarek@broadcom.com>
Signed-off-by: Vikas Gupta <vikas.gupta@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>