Move flavour-specific parts out of common cpio.c file and

rename remaining to cpio_common.c

include/grub/fat.h

@@ -29,13 +29,18 @@ struct grub_fat_bpb
   grub_uint8_t sectors_per_cluster;
   grub_uint16_t num_reserved_sectors;
   grub_uint8_t num_fats;
+  /* 0x10 */
   grub_uint16_t num_root_entries;
   grub_uint16_t num_total_sectors_16;
   grub_uint8_t media;
+  /*0 x15 */
   grub_uint16_t sectors_per_fat_16;
   grub_uint16_t sectors_per_track;
+  /*0 x19 */
   grub_uint16_t num_heads;
+  /*0 x1b */
   grub_uint32_t num_hidden_sectors;
+  /* 0x1f */
   grub_uint32_t num_total_sectors_32;
   union
   {