x86/mm: Make kernel/check.c explicitly non-modular

The Kconfig currently controlling compilation of this code is:

  arch/x86/Kconfig:config X86_CHECK_BIOS_CORRUPTION
  arch/x86/Kconfig:       bool "Check for low memory corruption"

...meaning that it currently is not being built as a module by
anyone.

Lets remove the couple traces of modularity so that when reading
the code there is no doubt it is builtin-only.

Since module_init translates to device_initcall in the
non-modular case, the init ordering remains unchanged with this
commit.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1440459295-21814-4-git-send-email-paul.gortmaker@windriver.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

arch/x86/kernel/check.c

@@ -1,4 +1,4 @@
-#include <linux/module.h>
+#include <linux/init.h>
 #include <linux/sched.h>
 #include <linux/kthread.h>
 #include <linux/workqueue.h>
@@ -162,6 +162,5 @@ static int start_periodic_check_for_corruption(void)
 	schedule_delayed_work(&bios_check_work, 0);
 	return 0;
 }
-
-module_init(start_periodic_check_for_corruption);
+device_initcall(start_periodic_check_for_corruption);