usb: gadget: f_sdp: Allow SPL to load and boot FIT via SDP

Add support for loading u-boot FIT images over the USB SDP protocol in
the SPL

Signed-off-by: Frieder Schrempf <frieder.schrempf@kontron.de>
[Various build fixes]
Signed-off-by: Sjoerd Simons <sjoerd.simons@collabora.co.uk>
Tested-by: Fabio Estevam <festevam@gmail.com>
Tested-by: Lukasz Majewski <lukma@denx.de>
3 files changed