ext2: Make error message human readable

Say so, if the partition doesn't hold an ext2 filesystem.

Signed-off-by: Helge Deller <deller@gmx.de>
diff --git a/ipl/ext2.c b/ipl/ext2.c
index 81ebcac..6add1a0 100644
--- a/ipl/ext2.c
+++ b/ipl/ext2.c
@@ -288,7 +288,7 @@
 	
 	if (__le16_to_cpu(sb.s_magic) != EXT2_SUPER_MAGIC) {
 		if (!quiet) {
-			printf("ext2_init: bad magic 0x%x\n", sb.s_magic);
+			printf("This is not a ext2 filesystem (magic 0x%x)\n", sb.s_magic);
 		}
 		return -1;
 	}