Make "Show correction suggestions" as a binary option

Formerly "Show correction suggestions" had three options, "always
show", "show in portrait mode", and "always hide". The reason behind
"show in portrait mode" was that there may not be enough screen estate
in landscape mode to show suggestions. Because recent phone devices
have relatively large screen, we decide to remove "show in portrait
mode" option.

Bug: 15780939
Change-Id: I896d737452c3893d43ce20bd88127f10c1eb3d83