edac: initialize the core earlier

In order for it to work with it builtin, the EDAC core should
be initialized earlier, otherwise the ghes_edac driver initializes
before edac_mc_sysfs_init() being called:

...
[    4.998373] EDAC MC0: Giving out device to 'ghes_edac.c' 'ghes_edac': DEV ghes
...
[    4.998373] EDAC MC1: Giving out device to 'ghes_edac.c' 'ghes_edac': DEV ghes
[    6.519495] EDAC MC: Ver: 3.0.0
[    6.523749] EDAC DEBUG: edac_mc_sysfs_init: device mc created

The net result is that no EDAC sysfs nodes will appear.
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/edac/edac_module.c

@@ -146,7 +146,7 @@ static void __exit edac_exit(void)
 /*
  * Inform the kernel of our entry and exit points
  */
-module_init(edac_init);
+subsys_initcall(edac_init);
 module_exit(edac_exit);
 
 MODULE_LICENSE("GPL");