spi/topcliff_pch: Fix data transfer issue

It seems spi_topcliff_pch of linux-2.6.37-rc6 degraded by previous patch.
In fact, data transfer fails on evaluation board testing.
I found like the following register miss-setting line.
Using this patch, I have confirmed data transfer can work well.

Signed-off-by: Tomoya MORINAGA <tomoya-linux@dsn.okisemi.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>