codal_app/microbithal: Remove now-unused microbit_hal_display_clear.

Signed-off-by: Damien George <damien@micropython.org>

Author: dpgeorge

src/codal_app/microbithal.cpp

@@ -319,10 +319,6 @@ void microbit_hal_display_enable(int value) {
     }
 }
 
-void microbit_hal_display_clear(void) {
-    uBit.display.clear();
-}
-
 int microbit_hal_display_get_pixel(int x, int y) {
     uint32_t pixel = uBit.display.image.getPixelValue(x, y);
     if (pixel == 255) {

src/codal_app/microbithal.h

@@ -138,7 +138,6 @@ int microbit_hal_spi_transfer(size_t len, const uint8_t *src, uint8_t *dest);
 int microbit_hal_button_state(int button, int *was_pressed, int *num_presses);
 
 void microbit_hal_display_enable(int value);
-void microbit_hal_display_clear(void);
 int microbit_hal_display_get_pixel(int x, int y);
 void microbit_hal_display_set_pixel(int x, int y, int bright);
 int microbit_hal_display_read_light_level(void);