[coreboot] [patch] flashrom: resending my patch about SPI/LPC conflicts

[Bao, Zheng]

Signed-off-by: Zheng Bao

This patch is about flashrom running on dbm690t. It was sent several
months ago and hasn't got any response yet. Now it deals with 3
problems.
1. Fix the bug that the flashrom would hang if there is not SPI chip. A
timeout detection was added.
2. We only access LPC ROM if we boot via LPC ROM. And only SPI ROM if we
boot via SPI ROM. Doing crossly is not allowed. Anybody has better idea?
3. When we read/write SPI, we use memory read/write instead of sending
SPI command.

Joe