Unify non-shifted and shifted JEDEC access.

Some Parallel bus chips have a 16-bit mode and an 8-bit mode. They use
normal JEDEC addresses for 16-bit mode and shifted addresses (by 1 bit)
for 8-bit mode. Some programmers can access them in 16-bit mode, but on
all flashrom-supported programmers so far, we access them in 8-bit mode.
This means we have to shift the addresses but apart from the addresses
we can share the code.

This patch makes this possible by checking the chip's FEATURE_ADDR_SHIFTED
flag in common JEDEC functions and applying the right addresses respectively.

Signed-off-by: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006@gmx.net>
Signed-off-by: Stefan Tauner <stefan.tauner@alumni.tuwien.ac.at>
Acked-by: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006@gmx.net>

git-svn-id: svn://flashrom.org/flashrom/trunk@1840 2b7e53f0-3cfb-0310-b3e9-8179ed1497e1