remove "struct subsystem" as it is no longer needed

We need to work on cleaning up the relationship between kobjects, ksets and
ktypes.  The removal of 'struct subsystem' is the first step of this,
especially as it is not really needed at all.

Thanks to Kay for fixing the bugs in this patch.

Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/firmware/efivars.c b/drivers/firmware/efivars.c
index c6281cc..1324984 100644
--- a/drivers/firmware/efivars.c
+++ b/drivers/firmware/efivars.c
@@ -409,7 +409,7 @@
 };
 
 static ssize_t
-dummy(struct subsystem *sub, char *buf)
+dummy(struct kset *kset, char *buf)
 {
 	return -ENODEV;
 }
@@ -422,7 +422,7 @@
 
 
 static ssize_t
-efivar_create(struct subsystem *sub, const char *buf, size_t count)
+efivar_create(struct kset *kset, const char *buf, size_t count)
 {
 	struct efi_variable *new_var = (struct efi_variable *)buf;
 	struct efivar_entry *search_efivar, *n;
@@ -480,7 +480,7 @@
 }
 
 static ssize_t
-efivar_delete(struct subsystem *sub, const char *buf, size_t count)
+efivar_delete(struct kset *kset, const char *buf, size_t count)
 {
 	struct efi_variable *del_var = (struct efi_variable *)buf;
 	struct efivar_entry *search_efivar, *n;
@@ -551,11 +551,11 @@
  * the efivars driver
  */
 static ssize_t
-systab_read(struct subsystem *entry, char *buf)
+systab_read(struct kset *kset, char *buf)
 {
 	char *str = buf;
 
-	if (!entry || !buf)
+	if (!kset || !buf)
 		return -EINVAL;
 
 	if (efi.mps != EFI_INVALID_TABLE_ADDR)
@@ -687,7 +687,7 @@
 		goto out_free;
 	}
 
-	kset_set_kset_s(&vars_subsys, efi_subsys);
+	kobj_set_kset_s(&vars_subsys, efi_subsys);
 
 	error = subsystem_register(&vars_subsys);