loader/multiboot_mbi2: Use central copy of grub_efi_find_mmap_size()

Delete local copy of function to determine required buffer size for the
UEFI memory map, use helper in kern/efi/mm.c.

Signed-off-by: Leif Lindholm <leif.lindholm@linaro.org>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>

grub-core/loader/multiboot_mbi2.c

@@ -411,42 +411,6 @@ acpiv2_size (void)
 
 static grub_efi_uintn_t efi_mmap_size = 0;
 
-/* Find the optimal number of pages for the memory map. Is it better to
-   move this code to efi/mm.c?  */
-static void
-find_efi_mmap_size (void)
-{
-  efi_mmap_size = (1 << 12);
-  while (1)
-    {
-      int ret;
-      grub_efi_memory_descriptor_t *mmap;
-      grub_efi_uintn_t desc_size;
-      grub_efi_uintn_t cur_mmap_size = efi_mmap_size;
-
-      mmap = grub_malloc (cur_mmap_size);
-      if (! mmap)
-	return;
-
-      ret = grub_efi_get_memory_map (&cur_mmap_size, mmap, 0, &desc_size, 0);
-      grub_free (mmap);
-
-      if (ret < 0)
-	return;
-      else if (ret > 0)
-	break;
-
-      if (efi_mmap_size < cur_mmap_size)
-	efi_mmap_size = cur_mmap_size;
-      efi_mmap_size += (1 << 12);
-    }
-
-  /* Increase the size a bit for safety, because GRUB allocates more on
-     later, and EFI itself may allocate more.  */
-  efi_mmap_size += (3 << 12);
-
-  efi_mmap_size = ALIGN_UP (efi_mmap_size, 4096);
-}
 #endif
 
 static grub_size_t
@@ -467,7 +431,7 @@ grub_multiboot2_get_mbi_size (void)
 {
 #ifdef GRUB_MACHINE_EFI
   if (!keep_bs && !efi_mmap_size)
-    find_efi_mmap_size ();    
+    efi_mmap_size = grub_efi_find_mmap_size ();
 #endif
   return 2 * sizeof (grub_uint32_t) + sizeof (struct multiboot_tag)
     + sizeof (struct multiboot_tag)