treewide: replace min/max macros by non-exported MIN/MAX and deprecate them

[metux]

Replace public min/max macros by private MIN/MAX and deprecate them. The few drivers still using them can trivially define them on their own. Adding a new private header for all kind of math-ish definitions - future commits will move more stuff there.

Signed-off-by: Enrico Weigelt, metux IT consult [email protected]