fastrpc: hexagonrpcd: listener: switch to interp3

For a proper transition to version 3 of the method definitions, switch
the reverse tunnel to version 3.

Author: flamingradian

hexagonrpcd/listener.c

@@ -24,6 +24,7 @@
 #include <libhexagonrpc/fastrpc.h>
 #include <libhexagonrpc/interfaces/remotectl.def>
 #include <stddef.h>
+#include <stdint.h>
 #include <stdio.h>
 
 #include "interfaces/adsp_listener.def"
@@ -220,6 +221,13 @@ static int invoke_requested_procedure(size_t n_ifaces,
 	uint32_t method = REMOTE_SCALARS_METHOD(sc);
 	int ret;
 
+	if (method < 31)
+		method = REMOTE_SCALARS_METHOD(sc);
+	else if (decoded[0].s >= sizeof(uint32_t))
+		method = *(const uint32_t *) decoded[0].p;
+	else
+		method = UINT32_MAX;
+
 	if (sc & 0xff) {
 		fprintf(stderr, "Handles are not supported, but got %u in, %u out\n",
 				(sc & 0xf0) >> 4, sc & 0xf);