mcs: use JEIDA signalling by default

Signed-off-by: Eric Nelson <eric.nelson@boundarydevices.com>
mcs: display splash in PREBOOT

Signed-off-by: Eric Nelson <eric.nelson@boundarydevices.com>
mcs: Don't use display for U-Boot output by default

Signed-off-by: Eric Nelson <eric.nelson@boundarydevices.com>
mcs: add savesplash utility to store mcs.bmp.gz into serial EEPROM

Signed-off-by: Eric Nelson <eric.nelson@boundarydevices.com>
mcs: Don't display U-Boot version string

Signed-off-by: Eric Nelson <eric.nelson@boundarydevices.com>