Commit cb57a2b4cff7edf2a4e32c0163200e9434807e0a ("x86-32: Export
kernel_stack_pointer() for modules") added an include of the
module.h header in conjunction with adding an EXPORT_SYMBOL_GPL
of kernel_stack_pointer.
But module.h should be avoided for simple exports, since it in turn
includes the world. Swap the module.h for export.h instead.