8.x backward compatibility

[FoamyGuy]

I have not tested on hardware.

I think this will work as a solution for adafruit/Adafruit_CircuitPython_SSD1322#21 to allow that display driver and a few others to work under blinka displayio.

[makermelissa]

I'd like this tested before merging as this library is sufficiently complex enough that something like this might break it (though I doubt it).

[FoamyGuy]

I've tested this successfully now on a Raspberry Pi 3 B+, flashed with latest RasPi OS. My testing was with this example script: https://github.com/adafruit/Adafruit_CircuitPython_ILI9341/blob/main/examples/ili9341_pitft_simpletest.py

I ran it two ways:

1. With this PR branch of Blinka_DisplayIO and the currently released ILI9341 driver which has the new 9.x API
2. With this PR branch of Blinka_DisplayIO and the ILI9341 driver modified to have only the old 8.x API:

from displayio import FourWire
from displayio import Display
# ....
class ILI9341(Display):

As far as I can tell everything is working as expected in both cases.

[makermelissa]

Awesome, that works for me.

[makermelissa]

Looks good. Thanks.