configs: add defconfig for TS-4800
The TS-4800 is supported by mainline Linux as of 4.5 and by U-boot
as of v2016-07.
The package requires the custom ts4800-mbrboot routine.
A post-image script is provided to generate an image that can be
directly written to an SD card.
More details on the board here:
http://wiki.embeddedarm.com/wiki/TS-4800
Signed-off-by: Damien Riegel <damien.riegel@savoirfairelinux.com>
Signed-off-by: Patrick Keroulas <patrick.keroulas@savoirfairelinux.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>