YUKAWA: bump up device/amlogic/yukawa and device/amlogic/yukawa-kernel

Adds BayLibre's remotes for the yukawa and yukawa-kernel repos to include SD Card issue on System UI and BT enablement issue.

Also, in order to have a simpler "repo init" command, default.xml is a symbolic link to a Khadas manifest.

Signed-off-by: Vitor Sato Eschholz vsatoes@baylibre.com