Kernel: Add an x86 include check+error in x86/RegisterState.h

Author: https://github.com/jamesmintram
Commit: 34b341e35d
Pull-request: https://github.com/SerenityOS/serenity/pull/11141
Reviewed-by: https://github.com/bgianfo ✅
Reviewed-by: https://github.com/kleinesfilmroellchen ✅

Kernel/Arch/x86/RegisterState.h

@@ -12,6 +12,9 @@
 #include <Kernel/Arch/x86/ASM_wrapper.h>
 #include <Kernel/Arch/x86/CPU.h>
 
+#include <AK/Platform.h>
+VALIDATE_IS_X86()
+
 namespace Kernel {
 
 struct [[gnu::packed]] RegisterState {