eeprom: Rename bootsrc to rootsrc

The kernel always comes off of the SD card, the flag really tells where
the root filesystem will live.

Signed-off-by: Sean Cross <xobs@kosagi.com>
eepromdev: Get rid of C++ enum

There is already a C enum, so get rid of the enum in the EepromDev class.

Signed-off-by: Sean Cross <xobs@kosagi.com>
retina: Treat the retina feature as an IT6251-present flag

In v1, the feature_retina indicated whether a high-resolution screen was
attached.  Now that we use individual channels to configure that, repurpose
this flag to indicate whether there is an IT6251 present or not.

Signed-off-by: Sean Cross <xobs@kosagi.com>