mmc: add HS200 support in MMC core

Add HS200 to the list of supported modes and introduce tuning in the MMC
startup process.

Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Jean-Jacques Hiblot <jjhiblot@ti.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
2 files changed