[PATCH v3] firmware/sysfb: Fix VESA format selection

[Pierre Asselin]

I went back to nested max3() after all as Thomas asked.  My first cut
had casts in the innermost max3() and the code looked truly awful.  I
decided that two casts are tolerable.  I added a comment to explain
the casts.

Against clamp_t(u8,lfb_depth,1,32): the clamp_t() macro does no
typechecking;  might as well just cast lfb_depth to u8, but that assumes
the value would fit (positively crazy if it doesn't, but still.)
Instead, I widen the other two args of the outer max3().

--PA