writeprotect.c: Split register value/mask calculation into pure func

Extract the code that converts `struct wp_bits` into a collection of
register values and bit masks out of `write_wp_bits()` into a new
function.

This avoids monadic transformer stacks where unit-testing cannot
penetrate well to give suitable coverage, therefore keep the bit
logic in a separate pure function.

Tested: ninja test
Tested: flashrom --wp-{{dis,en}able,range,list,status} on dedede

Change-Id: I604478ecbb70392c5584bf5d87c76b6f20f882b1
Signed-off-by: Nikolai Artemiev <nartemiev@google.com>
Original-Reviewed-on: https://review.coreboot.org/c/flashrom/+/69846
Original-Reviewed-by: Sergii Dmytruk <sergii.dmytruk@3mdeb.com>
Original-Reviewed-by: Edward O'Callaghan <quasisec@chromium.org>
Reviewed-on: https://review.coreboot.org/c/flashrom-stable/+/71013
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Nico Huber <nico.h@gmx.de>
1 file changed