x86/efi: Replace efi_pgd with efi_mm.pgd

Since the previous patch added support for efi_mm, let's handle efi_pgd
through efi_mm and remove global variable efi_pgd.

Tested-by: Bhupesh Sharma <bhsharma@redhat.com>
Signed-off-by: Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Lee, Chun-Yi <jlee@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi Shankar <ravi.v.shankar@intel.com>
Cc: Ricardo Neri <ricardo.neri@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: linux-efi@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
diff --git a/arch/x86/mm/debug_pagetables.c b/arch/x86/mm/debug_pagetables.c
index 51a6f92..225fe2f 100644
--- a/arch/x86/mm/debug_pagetables.c
+++ b/arch/x86/mm/debug_pagetables.c
@@ -1,4 +1,5 @@
 #include <linux/debugfs.h>
+#include <linux/efi.h>
 #include <linux/module.h>
 #include <linux/seq_file.h>
 #include <asm/pgtable.h>
@@ -73,13 +74,12 @@ static const struct file_operations ptdump_curusr_fops = {
 #endif
 
 #if defined(CONFIG_EFI) && defined(CONFIG_X86_64)
-extern pgd_t *efi_pgd;
 static struct dentry *pe_efi;
 
 static int ptdump_show_efi(struct seq_file *m, void *v)
 {
-	if (efi_pgd)
-		ptdump_walk_pgd_level_debugfs(m, efi_pgd, false);
+	if (efi_mm.pgd)
+		ptdump_walk_pgd_level_debugfs(m, efi_mm.pgd, false);
 	return 0;
 }