SCREEN_WIDTH is visible area already, not addressable area

- sh1106 starts showing from column 2 (the library handles the offsets) so we don't actually need
the different screen width here.

src/screen.cpp

@@ -35,11 +35,8 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 #define FONT_HEIGHT 14 // actually 13 for "ariel 10" but want a little extra space
 #define FONT_HEIGHT_16 (ArialMT_Plain_16[1] + 1)
-#ifdef USE_SH1106
-#define SCREEN_WIDTH 132
-#else
+// This means the *visible* area (sh1106 can address 132, but shows 128 for example)
 #define SCREEN_WIDTH 128
-#endif
 #define SCREEN_HEIGHT 64
 #define TRANSITION_FRAMERATE 30 // fps
 #define IDLE_FRAMERATE 10       // in fps