Kernel: Move smp_initialized flag after schedulers are initialized

Before this real hardware failed to boot with smp enabled. Allocating
the idle thread does a page mapping which ends up broadcasting TLB
shootdown to other processes. This ends up failing somewhere halting the
processors never allowing them to initialize their scheduler

kernel/kernel/Processor.cpp

@@ -189,8 +189,6 @@ namespace Kernel
 				__builtin_ia32_pause();
 			}
 		}
-
-		s_is_smp_enabled = true;
 	}
 
 	void Processor::handle_ipi()

kernel/kernel/Scheduler.cpp

@@ -136,6 +136,9 @@ namespace Kernel
 		while (s_schedulers_initialized < Processor::count())
 			__builtin_ia32_pause();
 
+		if (Processor::count() > 1)
+			Processor::set_smp_enabled();
+
 		return {};
 	}