commands: Remove trailing whitespaces

Signed-off-by: Elyes Haouas <ehaouas@noos.fr>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>

grub-core/commands/i386/pc/drivemap.c

@@ -185,7 +185,7 @@ list_mappings (void)
       return GRUB_ERR_NONE;
     }
 
-  /* TRANSLATORS:  This is the header of mapping list. 
+  /* TRANSLATORS:  This is the header of mapping list.
      On the left is how OS will see the disks and
      on the right current GRUB vision.  */
   grub_puts_ (N_("OS disk #num ------> GRUB/BIOS device"));