EmbeddedPkg/MmcDxe: Add non-DDR timing mode support
Only DDR mode is support for 8bit mode currently. Add
non-DDR case when configuring ECSD.
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Jun Nie <jun.nie@linaro.org>
Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org>