dummyflasher: enforce write protection for W25Q128FV

Start taking bits related to write protection into account.

Also add "hwwp" parameter for dummy programmer that sets state of WP
pin (not inverted value).

TEST=use command-line interface to run WP-related commands

dummyflasher doesn't store state of the chip between runs and flashrom
allows running only one command, so testing WP in this way is limited.
However, WP options can be combined with other operations and are
executed prior to them, so certain scenarios can be checked.

List possible ranges:
    flashrom -p dummy:emulate=W25Q128FV,hwwp=yes --wp-list

Set a particular range and check status is correct:
    flashrom -p dummy:emulate=W25Q128FV,hwwp=yes \
             --wp-enable \
             --wp-range=0x00100000,0x00f00000 \
             --wp-status

Enable write protection and try erasing/writing (erasing here):
    # this fails
    flashrom -p dummy:emulate=W25Q128FV,hwwp=yes \
             --wp-range=0,0x00c00000 \
             --wp-enable \
             --erase

Write protecting empty range has no effect:
    # this succeeds
    flashrom -p dummy:emulate=W25Q128FV,hwwp=yes \
             --wp-range=0,0 \
             --wp-enable \
             --erase

Disabling WP is possible if hwwp is off:
    # this fails
    flashrom -p dummy:emulate=W25Q128FV,spi_status=0x80,hwwp=yes \
             --wp-disable
    # this succeeds
    flashrom -p dummy:emulate=W25Q128FV,spi_status=0x80,hwwp=no \
             --wp-disable

Change-Id: I9fd1417f941186391bd213bd355530143c8f04a0
Signed-off-by: Sergii Dmytruk <sergii.dmytruk@3mdeb.com>
---
M dummyflasher.c
M flashrom.8.tmpl
2 files changed, 157 insertions(+), 18 deletions(-)