efi: Deduplicate configuration table search function

We do table search in many places doing exactly the same algorithm.
The only minor variance in users is which table is used if several entries
are present. As specification mandates uniqueness and even if it ever isn't,
first entry is good enough, unify this code and always use the first entry.

Signed-off-by: Vladimir Serbinenko <phcoder@gmail.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>

grub-core/commands/efi/lssal.c

@@ -136,22 +136,16 @@ grub_cmd_lssal (struct grub_command *cmd __attribute__ ((unused)),
 		int argc __attribute__ ((unused)),
 		char **args __attribute__ ((unused)))
 {
-  const grub_efi_system_table_t *st = grub_efi_system_table;
-  grub_efi_configuration_table_t *t = st->configuration_table;
-  unsigned int i;
   static grub_guid_t guid = GRUB_EFI_SAL_TABLE_GUID;
+  void *table = grub_efi_find_configuration_table (&guid);
 
-  for (i = 0; i < st->num_table_entries; i++)
+  if (table == NULL)
     {
-      if (grub_memcmp (&guid, &t->vendor_guid,
-		       sizeof (grub_guid_t)) == 0)
-	{
-	  disp_sal (t->vendor_table);
-	  return GRUB_ERR_NONE;
-	}
-      t++;
+      grub_printf ("SAL not found\n");
+      return GRUB_ERR_NONE;
     }
-  grub_printf ("SAL not found\n");
+
+  disp_sal (table);
   return GRUB_ERR_NONE;
 }