gui: Remove show/hide selection option in lists

The implementation of the "show_selection_marker" option in
lists isn't great. It's a cosmetic option used to hide the
selection, but it causes the list to do funny things to the
selected_item and doesn't play nice with voiced menus, since
these rely on the selection to determine what item is spoken.

There are only two user-facing lists that use the option, the
"Rockbox Info" screen and a menu in the superdom plugin. The
rest are debug screens, and cosmetics don't matter much there.

Given how little used the option is, and its issues, removing
it seems reasonable.

Change-Id: I2c70b3e4c74ff3cc6dbac46366a371d271dd2d58

0 files changed, 0 insertions, 0 deletions