spi: ich: Change PCHV_ to ICHV_

The ICH SPI controller supports two variants, one of which is ICH7
compatible and the other is ICH9 compatible. Change 'pch_version'
to 'ich_version' to better match its original name.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Jagan Teki <jteki@openedev.com>
Tested-by: Simon Glass <sjg@chromium.org>