Fix emulated mode prerequisites in Relay BP guide

Emulated mode requires GPUDirect RDMA (same as FPGA mode).
Note loopback cable requirement in hardware table. Replace
libibverbs mention with reference to cuda-quantum realtime
build guide for complete software dependency listing.

Signed-off-by: Chuck Ketcham <cketcham@nvidia.com>

Author: cketcham2333

docs/realtime_qldpc_relay_bp_guide.md

@@ -30,7 +30,7 @@ configurations:
 | Configuration | GPU | ConnectX NIC | FPGA |
 |---|---|---|---|
 | CI unit test | Any CUDA-capable GPU | Not required | Not required |
-| Emulated E2E | Any CUDA-capable GPU | Required (loopback cable) | Not required |
+| Emulated E2E | CUDA GPU with GPUDirect RDMA | Required (loopback cable) | Not required |
 | FPGA E2E | CUDA GPU with GPUDirect RDMA | Required | Required |
 
 Tested platforms: DGX Spark, GB200.
@@ -255,7 +255,8 @@ processes run concurrently:
 
 - ConnectX NIC with a loopback cable connecting both ports (the emulator
   sends RDMA traffic out one port and the bridge receives on the other)
-- `libibverbs` / RDMA-capable network stack
+- Software dependencies (DOCA, Holoscan SDK, etc.) as described in the
+  [cuda-quantum realtime build guide](https://github.com/NVIDIA/cuda-quantum/blob/main/realtime/docs/building.md)
 - All three tools built (bridge, playback, emulator)
 
 ### Running