minix: describe usage of different magic numbers

One can get this information from minix/inode.c, but adding the
explanations at the definition sites is more appropriate.
Signed-off-by: Sami Kerola <kerolasa@iki.fi>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/linux/magic.h

@@ -30,11 +30,11 @@
 #define ANON_INODE_FS_MAGIC	0x09041934
 #define PSTOREFS_MAGIC		0x6165676C
 
-#define MINIX_SUPER_MAGIC	0x137F		/* original minix fs */
-#define MINIX_SUPER_MAGIC2	0x138F		/* minix fs, 30 char names */
-#define MINIX2_SUPER_MAGIC	0x2468		/* minix V2 fs */
-#define MINIX2_SUPER_MAGIC2	0x2478		/* minix V2 fs, 30 char names */
-#define MINIX3_SUPER_MAGIC	0x4d5a		/* minix V3 fs */
+#define MINIX_SUPER_MAGIC	0x137F		/* minix v1 fs, 14 char names */
+#define MINIX_SUPER_MAGIC2	0x138F		/* minix v1 fs, 30 char names */
+#define MINIX2_SUPER_MAGIC	0x2468		/* minix v2 fs, 14 char names */
+#define MINIX2_SUPER_MAGIC2	0x2478		/* minix v2 fs, 30 char names */
+#define MINIX3_SUPER_MAGIC	0x4d5a		/* minix v3 fs, 60 char names */
 
 #define MSDOS_SUPER_MAGIC	0x4d44		/* MD */
 #define NCP_SUPER_MAGIC		0x564c		/* Guess, what 0x564c is :-) */