serial: max310x: add comments for PLL limits

Add comments to help clarify the provenance of the various hardcoded values
used in computing the ref clk.

Assisted-by: Gemini:Pro
Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Link: https://patch.msgid.link/20260417-max310x-2-v1-10-b424e105ecac@dimonoff.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
1 file changed