[debugging] Fix gdb script koid refs & panic CPU display

Two minor debugging helpers:

- the GDB script was still referencing m_koid on objects, switched to
  the replacement m_obj_id instead.
- finally gave in and made panic print 1-based CPU ids like GDB uses
  instead of 0-based like the hardware and LITERALLY EVERYTHING ELSE

src/kernel/panic.serial/display.cpp

@@ -38,7 +38,7 @@ print_cpu(serial_port &out, cpu_data &cpu)
 {
     out.write("\n \e[0;31m==[ CPU: ");
     char cpuid[7];
-    util::format({cpuid, sizeof(cpuid)}, "%4x", cpu.id);
+    util::format({cpuid, sizeof(cpuid)}, "%4d", cpu.id + 1); // gdb uses 1-based CPU indices
     out.write(cpuid);
     out.write(" ]====================================================================\n");
 }