shell: Don't allow maximized surfaces to be moved with touch
shell: Don't allow maximized surfaces to be moved with touch

Moving a maximized surface with the pointer is already not possible,
so make the behavior with touch consistent.

https://bugs.freedesktop.org/show_bug.cgi?id=78208

Fantu/compositor-spice,udoprog/weston,xorgy/weston,sir-murray/weston,giucam/weston,sir-murray/weston,giucam/weston,Fantu/compositor-spice,kwm81/weston,Fantu/compositor-spice,mchalupa/weston,Tarnyko/weston-xdg_surface_present,xorgy/weston,kwm81/weston,Gnurou/weston,eyolfson/weston,krezovic/weston,mchalupa/weston,jonnylamb/weston,Gnurou/weston,udoprog/weston,Tarnyko/weston-xdg_surface_present,krezovic/weston,jonnylamb/weston,eyolfson/weston