Pico ePaper 4.2" drivers: default 0 arg for .do_refresh.

drivers/epaper/pico_epaper_42.py

@@ -257,7 +257,7 @@ class EPD(framebuf.FrameBuffer):
 
     # Specific method for micro-gui. Unsuitable EPD's lack this method. Micro-gui
     # does not test for asyncio as this is guaranteed to be up.
-    async def do_refresh(self, split):
+    async def do_refresh(self, split=0):
         assert not self._busy, "Refresh while busy"
         await self._as_show()  # split=5
 

drivers/epaper/pico_epaper_42_v2.py

@@ -227,7 +227,7 @@ class EPD(framebuf.FrameBuffer):
         return inner
 
     # micro-gui API; asyncio is running.
-    async def do_refresh(self, split):  # split = 5
+    async def do_refresh(self, split=0):  # split = 5
         assert not self._busy, "Refresh while busy"
         if self._partial:
             await self._as_show_partial()