i2c-piix4: Increase the intitial delay for the ServerWorks CSB5

Per the PIIX4 errata, there maybe a delay between setting the
start bit in the Smbus Host Controller Register and the transaction
actually starting. If the driver doesn't delay long enough, it
may appear that the transaction is complete when actually it
hasn't started, this may lead to bus collisions.

While 1 ms appears to be enough for most chips, the ServerWorks CSB5
wants 2 ms.

Signed-off-by: David Milburn <dmilburn@redhat.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>