Clean the function up by getting rid of all the insane XOR-leftshift
combos when assembling register values. While at it, remove all the
ad-hoc variables necessary for this XOR-leftshift voodoo. Finally,
get rid of the iterative division implementation of two constants
and replace it with a DIV_ROUND_UP() macro :-)
Signed-off-by: Marek Vasut <marex@denx.de>