mcu: Rename add_config_object() to register_config_callback()

Change the name of the config registration method and pass an explicit
reference to the callback to the new method.  This makes the
relationship between mcu registration and build_config() more clear in
the calling code.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

klippy/extras/display/hd44780.py

@@ -33,7 +33,7 @@ class HD44780:
         self.pins = [pin_params['pin'] for pin_params in pins]
         self.mcu = mcu
         self.oid = self.mcu.create_oid()
-        self.mcu.add_config_object(self)
+        self.mcu.register_config_callback(self.build_config)
         self.send_data_cmd = self.send_cmds_cmd = None
         # framebuffers
         self.text_framebuffer = (bytearray(' '*80), bytearray('~'*80), 0x80)

klippy/extras/display/st7920.py

@@ -27,7 +27,7 @@ class ST7920:
         self.pins = [pin_params['pin'] for pin_params in pins]
         self.mcu = mcu
         self.oid = self.mcu.create_oid()
-        self.mcu.add_config_object(self)
+        self.mcu.register_config_callback(self.build_config)
         self.send_data_cmd = self.send_cmds_cmd = None
         self.is_extended = False
         # framebuffers

klippy/extras/display/uc1701.py

@@ -28,7 +28,7 @@ class UC1701:
         self.mcu = mcu
         self.spi_oid = self.mcu.create_oid()
         self.a0_oid = self.mcu.create_oid()
-        self.mcu.add_config_object(self)
+        self.mcu.register_config_callback(self.build_config)
         self.glyph_buffer = []
         self.spi_xfer_cmd = self.set_pin_cmd = None
         self.vram = ([bytearray(128) for i in range(8)],