Enable USB HID commands to address all 128 display columns

The ColumnAddr (0x21) command in matrix_render_direct() was erroneously
setting the column end address to 125 instead of 127, which made it
impossible to address the rightmost two columns of pixels on the display
from USB HID 'WBIT' commands.

The 126 pixel limit exists for text and graphics drawn by the keyboard
firmware to simplify text drawing, since the firmware font width is 6px
per character, and 126 / 6 == 21, a nice round number.
I see no reason to impose this limit on arbitrary bitmap content drawn
by commands from the operating system.

reform2-keyboard-fw/oled.c

@@ -323,15 +323,15 @@ void matrix_render_direct(uint8_t* bitmap) {
   gfx_on();
 
   // Move to the home position
-  send_cmd3(PageAddr, 0, MatrixRows - 1);
-  send_cmd3(ColumnAddr, 0, (MatrixCols * FontWidth) - 1);
+  send_cmd3(PageAddr, 0, (DisplayHeight / 8) - 1);
+  send_cmd3(ColumnAddr, 0, DisplayWidth - 1);
 
   i2c_start_write(SSD1306_ADDRESS);
   i2c_master_write(0x40);
 
   int c = 0;
   for (uint16_t y=0; y<4; y++) {
-    for (uint16_t x=0; x<126; x++) {
+    for (uint16_t x=0; x<128; x++) {
       i2c_master_write(bitmap[c++]);
     }
   }