volume_id: add FAST_FUNC where appropriate

function                                             old     new   delta
volume_id_probe_iso9660                              324     327      +3
volume_id_probe_vfat                                 902     903      +1
volume_id_probe_udf                                  576     577      +1
volume_id_probe_ntfs                                 314     315      +1
uuidcache_check_device                               292     291      -1
volume_id_probe_xfs                                   87      85      -2
volume_id_probe_sysv                                 165     163      -2
volume_id_probe_romfs                                 89      87      -2
volume_id_probe_reiserfs                             236     234      -2
volume_id_probe_ocfs2                                 96      94      -2
volume_id_probe_luks                                  78      76      -2
volume_id_probe_linux_swap                           165     163      -2
volume_id_probe_jfs                                   96      94      -2
volume_id_probe_hfs_hfsplus                          795     793      -2
volume_id_probe_ext                                   82      80      -2
volume_id_probe_cramfs                                59      57      -2
volume_id_probe_btrfs                                 96      94      -2
free_volume_id                                        36      31      -5
volume_id_probe_linux_raid                           127     119      -8
volume_id_probe_all                                  152     138     -14
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 4/16 up/down: 6/-52)            Total: -46 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/util-linux/volume_id/unused_msdos.c b/util-linux/volume_id/unused_msdos.c
index 465f22d..ccec72c 100644
--- a/util-linux/volume_id/unused_msdos.c
+++ b/util-linux/volume_id/unused_msdos.c
@@ -47,7 +47,7 @@
 #define is_raid(type) \
 	(type == LINUX_RAID_PARTITION)
 
-int volume_id_probe_msdos_part_table(struct volume_id *id, uint64_t off)
+int FAST_FUNC volume_id_probe_msdos_part_table(struct volume_id *id, uint64_t off)
 {
 	const uint8_t *buf;
 	int i;