mmc: sdhci: fix caps2 for HS200

Although the HC supports HS200 (eMMC) the caps2 are always zero; this
means there's no way to use the super speed mode (when init the card).

If the HC support SDR104, for SD3.0, so it also supports HS200 for eMMC
and this patch just sets the MMC_CAP2_HS200 in the host caps2 field.

Reported-by: Youssef Triki <youssef.triki@st.com>
Signed-off-by: Giuseppe Cavallaro <peppe.cavallaro@st.com>
Reviewed-by: Philip Rakity <prakity@nvidia.com>
Signed-off-by: Chris Ball <cjb@laptop.org>