Compatibility with 96x48 Waveshare Matrix

Good day,

I'm trying to use this with this matrix: https://www.waveshare.com/wiki/RGB-Matrix-P2.5-96x48-F

I can initialise with `width=96`, but using `height=48` leads to error:

```
Traceback (most recent call last):
File "code.py", line 35, in
File "adafruit_matrixportal/matrixportal.py", line 96, in __init__
File "adafruit_matrixportal/graphics.py", line 67, in __init__
File "adafruit_matrixportal/matrix.py", line 209, in __init__
RuntimeError: Failed to initialize RGB Matrix
```

Here is my test code:

```
matrixportal = MatrixPortal(
url=DATA_SOURCE,
json_path=DATA_LOCATION,
status_neopixel=board.NEOPIXEL,
width=96,
height=48
)
```

When the height of the display is set to 32/64, it works, but doesn't display properly.

Reproduce the failure with the MatrixPortal initialization using width=96 and height=48, then trace the reported path through adafruit_matrixportal/matrixportal.py, graphics.py, and matrix.py. Compare it with the working height=32/64 cases and the linked Waveshare 96x48 matrix specification. Done means the 96x48 display initializes and renders correctly without the RuntimeError.

Written by the indexing model from the issue text.