drivers/rpmsg: fix Kconfig dependencies for RPMsg subsystem

[CV-Bowen]

Summary

This PR fixes the Kconfig dependency issues in the RPMSG subsystem to ensure proper configuration selection.

Changes:

1. drivers/rpmsg/Kconfig: Fix dependency chain for RPMSG-related options:

   • RPMSG_ROUTER now properly selects RPMSG
   • RPMSG_VIRTIO_LITE is now a hidden option (bool without prompt)
   • RPMSG_VIRTIO_IVSHMEM now selects RPMSG_VIRTIO_LITE instead of depending on it
   • Fix endif comment for SPI PM timeout (should cover both SPI and SPI_SLAVE)

2. arch/sim/Kconfig: Add new SIM_RPMSG_VIRTIO option that selects RPMSG_VIRTIO_LITE for simulator builds

3. boards/sim/sim/sim/configs: Update rpproxy_virtio and rpserver_virtio defconfigs to enable SIM_RPMSG_VIRTIO

Impact

• Stability: No impact - configuration-only changes
• Compatibility: No breaking changes
• Code Quality: Improves Kconfig organization and dependency handling

Testing

Build Verification:

# Build sim:rpserver_virtio
cmake -B cmake_out/rpserver_virtio -DBOARD_CONFIG=sim:rpserver_virtio -GNinja
cmake --build cmake_out/rpserver_virtio

# Build sim:rpproxy_virtio
cmake -B cmake_out/rpproxy_virtio -DBOARD_CONFIG=sim:rpproxy_virtio -GNinja
cmake --build cmake_out/rpproxy_virtio

Test Log:

❯ cmake_out/sim_server_virtio/nuttx

NuttShell (NSH) NuttX-12.12.0
server> 
server> 
server> cu

NuttShell (NSH) NuttX-12.12.0
proxy> 
proxy> 
proxy> 
proxy> ps
  TID   PID  PPID PRI POLICY   TYPE    NPX STATE    EVENT     SIGMASK            STACK COMMAND
    0     0     3   0 FIFO     Kthread   - Ready              0000000000000000 0069584 Idle_Task
    1     0     3 224 FIFO     Kthread   - Waiting  Semaphore 0000000000000000 0067456 sim_loop_wq 0x764146c003b0 0x764146c00430
    2     0     3 224 FIFO     Kthread   - Waiting  Semaphore 0000000000000000 0067472 hpwork 0x400aa0e0 0x400aa160
    3     3     0 100 FIFO     Task      - Running            0000000000000000 0067496 nsh_main
    4     0     3 224 FIFO     Kthread   - Waiting  Semaphore 0000000000000000 0067448 rpmsg_virtio server 0x764146c355c8
proxy> 
proxy> uname -a
NuttX proxy 12.12.0 d066538db9e-dirty Feb  3 2026 21:47:51 sim sim
proxy> server> 
server> uname -a
NuttX server 12.12.0 d066538db9e-dirty Feb  3 2026 21:47:40 sim sim
server> rpmsg ping all 1 1 1 1
[   23.420000] [server] ping times: 1
[   23.420000] [server] buffer_len: 2032, send_len: 17
[   23.420000] [server] avg: 0 s, 10165743 ns
[   23.420000] [server] min: 0 s, 10165743 ns
[   23.420000] [server] max: 0 s, 10165743 ns
[   23.420000] [server] rate: 0.013378 Mbits/sec
server> 
server> poweroff