[PATCH] partitions: Read Rio Karma partition table

The Rio Karma portable MP3 player has its own proprietary partition table.

The partition layout is similar to a DOS boot sector but it begins at a
different offset and uses a different magic number (0xAB56 instead of
0xAA55).  Add support for it to enable mounting the device.

Signed-off-by: Bob Copeland <me@bobcopeland.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>