Revert "BoardConfig: Disable hwcomposer legacy fallback"

This reverts commit 8f1414529107ca93fd1ed2f5c38ffb4d164cde3d.
hwc: Make build conditional

Signed-off-by: zombah <zombah@gmail.com>
keylayout: zoom is useless, bring brighness back until better times

Signed-off-by: zombah <zombah@gmail.com>
BoardConfig: Remove outdated vars and add hwc condition

Signed-off-by: zombah <zombah@gmail.com>