Since the ts4800_defconfig has been removed, the ts4800-mrboot package
is no longer useful, therefore we drop it.
Cc: Patrick Keroulas <patrick.keroulas@savoirfairelinux.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>