sbxxx: spibar[0] debug print refinements.

Newer models support a 66 MHz clock and fast reads.
We should probably distinguish the models better (as we do in ichspi)
and add support for frequency selection etc. For now this has to
suffice.

Signed-off-by: Stefan Tauner <stefan.tauner@student.tuwien.ac.at>
Acked-by: Stefan Tauner <stefan.tauner@student.tuwien.ac.at>

git-svn-id: svn://coreboot.org/flashrom/trunk@1678 2b7e53f0-3cfb-0310-b3e9-8179ed1497e1