Troubleshoot running multiple LCD displays.

[DocBohn]

As I'm shooting a video of the LCD1602 & LCD2004 side-by-side, we're seeing some surprising behavior on the LCD2004.

• \r (from the second row) goes to the first row.
• \f (from the second row) goes to the second row
  • \f at the start of a line seems to go to the first row (or, perhaps, \f from the third row goes to the first row)
• Advancing past the fourth row, with either \n or simply a too-long text, goes to the first row

[DocBohn]

If we start "Advancing past\nthe bottom\n" on the second row instead of the third, it correctly displays that text on the second and third rows, and then \n goes to the first row. But if we start "Advancing past\nthe bottom\n" on the third row, it correctly displays that text on the third and fourth rows, and then \n goes to the second row.

[DocBohn]

When it's just the LCD2004 without the LCD1602, everything behaves as expected.

[DocBohn]

We've already seen that running one LCD display over I2C and one over SPI won't work -- but that isn't surprising, given the current design. I'm not sure why the LCD1602 is mucking up the LCD2004 when they're both using I2C (with different addresses).

[DocBohn]

Current hypothesis (and this seem incredibly plausible) -- the ddram_address variable is not unique to each display. https://github.com/DocBohn/CowPi_stdio/blob/main/src/file_streams/hd44780_streams.c#L33