drivers: display: st7567: add display_clear support

Add support for `display_clear` API to the st7567 display.

Signed-off-by: Yishai Jaffe <yishai1999@gmail.com>

Author: yishai1999

drivers/display/display_st7567.c

@@ -454,6 +454,7 @@ static DEVICE_API(display, st7567_driver_api) = {
 	.blanking_on = st7567_suspend,
 	.blanking_off = st7567_resume,
 	.write = st7567_write,
+	.clear = st7567_clear,
 	.set_contrast = st7567_set_contrast,
 	.get_capabilities = st7567_get_capabilities,
 	.set_pixel_format = st7567_set_pixel_format,