ACPI: APEI: move edac_init ahead of ghes platform drv register

Commit dc4e8c0 ("ACPI: APEI: explicit init of HEST and GHES in
apci_init()") introduced a bug that invoking ghes_edac_register()
before edac_init(). Because at that time, the bus "edac" hasn't been
registered, this created sysfs /devices/mc0 instead of
/sys/devices/system/edac/mc/mc0 and caused a sysfs dup splat on an
Ampere eMag server:
 sysfs: cannot create duplicate filename '/devices/mc0'
 CPU: 19 PID: 1 Comm: swapper/0 Not tainted 5.19.0+ torvalds#138
 random: crng init done
 Hardware name: MiTAC RAPTOR EV-883832-X3-0001/RAPTOR, BIOS 0.14 02/22/2019
 Call trace:
  sysfs_warn_dup+0x6c/0x88
  sysfs_create_dir_ns+0xec/0x108
  kobject_add_internal+0xc0/0x328
  kobject_add+0x94/0x108
  device_add+0x104/0x8b0
  pmu_dev_alloc+0xb4/0x128
  perf_pmu_register+0x308/0x438
  xgene_pmu_dev_add+0x168/0x2c8
  acpi_pmu_dev_add+0x1f0/0x370
  acpi_ns_walk_namespace+0x16c/0x1ec
  acpi_walk_namespace+0xb0/0xf8
  xgene_pmu_probe+0x6b8/0x8a0
  platform_probe+0x70/0xe0
  really_probe+0x164/0x3b0
  __driver_probe_device+0x11c/0x190
  driver_probe_device+0x44/0xf8
  __driver_attach+0xc4/0x1b8
  bus_for_each_dev+0x78/0xd0
  driver_attach+0x2c/0x38
  bus_add_driver+0x150/0x240
  driver_register+0x6c/0x128
  __platform_driver_register+0x30/0x40
  xgene_pmu_driver_init+0x24/0x30
  do_one_initcall+0x50/0x248
  kernel_init_freeable+0x284/0x328
  kernel_init+0x2c/0x140
  ret_from_fork+0x10/0x20
 kobject_add_internal failed for mc0 with -EEXIST, don't try to register things with the same name in the same

This patch fixes it by moving edac_init() into acpi_ghes_init() and ahead of
platform_driver_register().

Fixes: dc4e8c0 ("ACPI: APEI: explicit init of HEST and GHES in apci_init()")
Signed-off-by: Jia He <justin.he@arm.com>
Cc: Shuai Xue <xueshuai@linux.alibaba.com>

drivers/acpi/apei/ghes.c

@@ -1462,6 +1462,7 @@ void __init acpi_ghes_init(void)
 	int rc;
 
 	sdei_init();
+	edac_init();
 
 	if (acpi_disabled)
 		return;

drivers/edac/edac_module.c

@@ -99,7 +99,7 @@ EXPORT_SYMBOL_GPL(edac_get_sysfs_subsys);
  * edac_init
  *      module initialization entry point
  */
-static int __init edac_init(void)
+int __init edac_init(void)
 {
 	int err = 0;
 
@@ -160,7 +160,6 @@ static void __exit edac_exit(void)
 /*
  * Inform the kernel of our entry and exit points
  */
-subsys_initcall(edac_init);
 module_exit(edac_exit);
 
 MODULE_LICENSE("GPL");

include/linux/edac.h

@@ -30,6 +30,7 @@ struct device;
 
 extern int edac_op_state;
 
+int __init edac_init(void);
 struct bus_type *edac_get_sysfs_subsys(void);
 
 static inline void opstate_init(void)