drivers: bluetooth: rpmsg: validate heap size configuration

Added a build-time assert to check if heap memory configuration to
make sure that it can accomodate RPMsg queue allocations.

Ref: NCSDK-5479

Signed-off-by: Kamil Piszczek <Kamil.Piszczek@nordicsemi.no>
diff --git a/drivers/bluetooth/hci/rpmsg_nrf53.c b/drivers/bluetooth/hci/rpmsg_nrf53.c
index b023906..d7b1431 100644
--- a/drivers/bluetooth/hci/rpmsg_nrf53.c
+++ b/drivers/bluetooth/hci/rpmsg_nrf53.c
@@ -48,6 +48,9 @@
 
 #define VDEV_STATUS_ADDR    SHM_BASE_ADDRESS
 
+BUILD_ASSERT(CONFIG_HEAP_MEM_POOL_SIZE >= 1024,
+	"Not enough heap memory for RPMsg queue allocation");
+
 /* End of configuration defines */
 
 static metal_phys_addr_t shm_physmap[] = { SHM_START_ADDR };