mmc: Add support for the no-mmc-hs400 prop

The linux commit f722e650d965 ("mmc: core: add support for disabling
HS400 mode via DT") added support for a no-mmc-hs400 prop.

Add support for the no-mmc-hs400 prop to disable HS400 host caps.

Signed-off-by: Jonas Karlman <jonas@kwiboo.se>
Reviewed-by: Dragan Simic <dsimic@manjaro.org>
Reviewed-by: Jaehoon Chung <jh80.chung@samsung.com>