mmc: sdhci: check 1.2v IO capability for SDHC host

Right now enable 1.2v IO voltage for SDHC is by using vqmmc.
Thus for the host which doesn't have vqmmc, or its vqmmc does
not support 1.2v, directly use MMC_CAP2_HS200 may cause HS200
failure.

So needs to check if vqmmc is able to support 1.2v. If it does
not support, disable 1.2v IO for HS200.

Signed-off-by: Chuanxiao Dong <chuanxiao.dong@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>