Fix aliasing issues found in ssd1322.c mentioned in (#1720)

[tlubke]

@dndrks I got my norns screen looking like the image on the right, but if you could checkout this branch and test again -- nothin' can beat a side-by-side comparison.

[catfact]

looking great here, nice work!

(i'd merge it now, but let's leave it separate for A/B convenience until the others get a look.)

[tehn]

fantastic!!

i'm going to merge this as the reference can be against main