footprint: Add bt_hci_rpmsg for the nRF5340 netcore

Add footprint tracking of the samples/bluetooth/hci_rpmsg
sample for the nRF5340. This is a BT controller-only build
for the nRF5340 with minimum features.

Signed-off-by: Emil Gydesen <[email protected]>

Author: Thalley

scripts/footprint/plan.txt

@@ -20,5 +20,6 @@ bt_central_hr,default,nrf52840dk_nrf52840,samples/bluetooth/central_hr,
 bt_mesh_demo,default,bbc_microbit,samples/bluetooth/mesh_demo,
 bt_hap_ha,default,nrf52840dk_nrf52840,samples/bluetooth/hap_ha,
 bt_hap_ha,default,nrf5340dk_nrf5340_cpuapp,samples/bluetooth/hap_ha,
+bt_hci_rpmsg,default,nrf5340dk_nrf5340_cpunet,samples/bluetooth/hci_rpmsg,
 sof,default,intel_adsp_cavs25,samples/subsys/audio/sof,
 sof,default,nxp_adsp_imx8,samples/subsys/audio/sof,