avrcp: Fix crash while handling unsupported events

The following crash can be observed if the remote peer send and
unsupported event:

ERROR: AddressSanitizer: heap-use-after-free on address 0x60b000148f11
 at pc 0x559644552088 bp 0x7ffe28b3c7b0 sp 0x7ffe28b3c7a0
 WRITE of size 1 at 0x60b000148f11 thread T0
     #0 0x559644552087 in avrcp_handle_event profiles/audio/avrcp.c:3907
     #1 0x559644536c22 in control_response profiles/audio/avctp.c:939
     #2 0x5596445379ab in session_cb profiles/audio/avctp.c:1108
     #3 0x7fbcb3e51c43 in g_main_context_dispatch (/lib/x86_64-linux-gnu/libglib-2.0.so.0+0x55c43)
     #4 0x7fbcb3ea66c7  (/lib/x86_64-linux-gnu/libglib-2.0.so.0+0xaa6c7)
     #5 0x7fbcb3e512b2 in g_main_loop_run (/lib/x86_64-linux-gnu/libglib-2.0.so.0+0x552b2)
     #6 0x559644754ab6 in mainloop_run src/shared/mainloop-glib.c:66
     #7 0x559644755606 in mainloop_run_with_signal src/shared/mainloop-notify.c:188
     #8 0x5596445bb963 in main src/main.c:1289
     #9 0x7fbcb3bafd8f in __libc_start_call_main ../sysdeps/nptl/libc_start_call_main.h:58
     #10 0x7fbcb3bafe3f in __libc_start_main_impl ../csu/libc-start.c:392
     #11 0x5596444e8224 in _start (/usr/local/libexec/bluetooth/bluetoothd+0xf0224)

profiles/audio/avrcp.c

@@ -3901,6 +3901,12 @@ static gboolean avrcp_handle_event(struct avctp *conn, uint8_t code,
 	case AVRCP_EVENT_UIDS_CHANGED:
 		avrcp_uids_changed(session, pdu);
 		break;
+	default:
+		if (event > AVRCP_EVENT_LAST) {
+			warn("Unsupported event: %u", event);
+			return FALSE;
+		}
+		break;
 	}
 
 	session->registered_events |= (1 << event);