FocusManager:focusTopLeftWidget(): only if hasDPad (#8737)
FocusManager:focusTopLeftWidget(): only if hasDPad (#8737)

Focusing (highlighting/inverting) widgets should not
happen on touch devices withoud DPad.
Frenzie/koreader,NiLuJe/koreader,koreader/koreader,Frenzie/koreader,NiLuJe/koreader,poire-z/koreader,poire-z/koreader,koreader/koreader