x86/mm/64: Make sync_global_pgds() static

The function is only called from within init_64.c and can be static.
Also remove it from pgtable_64.h.
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Mike Rapoport <rppt@linux.ibm.com>
Link: https://lore.kernel.org/r/20200721095953.6218-4-joro@8bytes.org

arch/x86/include/asm/pgtable_64.h

@@ -168,8 +168,6 @@ static inline void native_pgd_clear(pgd_t *pgd)
 	native_set_pgd(pgd, native_make_pgd(0));
 }
 
-extern void sync_global_pgds(unsigned long start, unsigned long end);
-
 /*
  * Conversion functions: convert a page and protection to a page entry,
  * and a page entry and page directory to the page they refer to.

arch/x86/mm/init_64.c

@@ -209,7 +209,7 @@ static void sync_global_pgds_l4(unsigned long start, unsigned long end)
  * When memory was added make sure all the processes MM have
  * suitable PGD entries in the local PGD level page.
  */
-void sync_global_pgds(unsigned long start, unsigned long end)
+static void sync_global_pgds(unsigned long start, unsigned long end)
 {
 	if (pgtable_l5_enabled())
 		sync_global_pgds_l5(start, end);