mmc: sdhci-sirf: fake version and capbility registers

chips have some issues for version and capbility registers, here we fake
them.

Signed-off-by: Weijun Yang <Weijun.Yang@csr.com>
Signed-off-by: Barry Song <Baohua.Song@csr.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>