USB: unusual_devs addition for RockChip MP3 player

This patch (as1136) adds an unusual_devs entry for a version of the
RockChip MP3 player which can't handle the MODE SENSE command used for
write-protect detection.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>