fix panic message in multicore_doorbell_claim_unused

src/rp2_common/pico_multicore/multicore.c

diff --git a/src/rp2_common/pico_multicore/multicore.c b/src/rp2_common/pico_multicore/multicore.c
index 453d770..ef9a9b0 100644
--- a/src/rp2_common/pico_multicore/multicore.c
+++ b/src/rp2_common/pico_multicore/multicore.c
@@ -371,7 +371,7 @@
     if (claimed_cores_for_doorbell & core_mask) {
         if (required) {
             panic( "Multicore doorbell %d already claimed on core mask 0x%x; requested core mask 0x%x\n",
-                   claimed_cores_for_doorbell, core_mask);
+                   doorbell_num, claimed_cores_for_doorbell, core_mask);
         }
         return false;
     } else {