correct byte order of raw-mp3 magic number (to be little-endian).

Reference: /n/sources/patch/applied/file-mp3-order
Date: Tue Apr 12 06:14:08 CES 2005

--- /sys/src/cmd/file.c	Tue Apr 12 06:13:42 2005
+++ /sys/src/cmd/file.c	Tue Apr 12 06:13:38 2005
@@ -523,7 +523,7 @@
 	0x04034B50,	0xFFFFFFFF,	"zip archive\n", "application/zip",
 	070707,		0xFFFF,		"cpio archive\n", OCTET,
 	0x2F7,		0xFFFF,		"tex dvi\n", "application/dvi",
-	0xfffa0000,	0xfffe0000,	"mp3 audio",	"audio/mpeg",
+	0xfaff,		0xfeff,		"mp3 audio\n",	"audio/mpeg",
 };
 
 int