Optiboot_dx not building again for custom lower baudrates

[tkoumrian]

Hi Spence,

I originally opened #490 when this happened Oct 2023, and you fixed it. I pulled the latest DxCore and found that the optboot_dx build is broken again for the 38400 baud that I need on 128DB. Building for 115200 succeeds and works, but ser1/ser2 alt_all_8sec not building at 38400.

[SpenceKonde]

No changes have been made to optiboot since that issue was posted. The old binary is still good. I don't remember what I did to get the extra space; the bootloaders are REALLY tight on flash, and I've done just about everything I can. I don't think it was something I considered proper to check in, as I would have checked it in if I thought it was fit for that

[tkoumrian]

diff'ing optiboot_dx.c shows that what I pulled when you asked me to test 2 years ago isn't the same as what's there, and it code changes and not formatting. I'll attach the file so you can compare and review rather than trying to post a diff. I believe you changed it after I pulled and tested, and that has broken it for the odd baudrates like 38400 that I'm trying to get.

optiboot_dx.c