RPC/RDMA: fix connection IRD/ORD setting

This logic sets the connection parameter that configures the local device
and informs the remote peer how many concurrent incoming RDMA_READ
requests are supported. The original logic didn't really do what was
intended for two reasons:

- The max number supported by the device is typically smaller than
any one factor in the calculation used, and

- The field in the connection parameter structure where the value is
stored is a u8 and always overflows for the default settings.

So what really happens is the value requested for responder resources
is the left over 8 bits from the "desired value". If the desired value
happened to be a multiple of 256, the result was zero and it wouldn't
connect at all.

Given the above and the fact that max_requests is almost always larger
than the max responder resources supported by the adapter, this patch
simplifies this logic and simply requests the max supported by the device,
subject to a reasonable limit.

This bug was found by Jim Schutt at Sandia.

Signed-off-by: Tom Tucker <tom@opengridcomputing.com>
Acked-by: Tom Talpey <talpey@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>