dash: remove USDHC3 card slot

Signed-off-by: Eric Nelson <eric.nelson@boundarydevices.com>
dash: Add LCD_BKLT_EN pin

Signed-off-by: Eric Nelson <eric.nelson@boundarydevices.com>
dash: configure LVDS_PWR_EN pin

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