MdeModulePkg/SdMmcPciHcDxe: Add UhsSignaling to SdMmcOverride protocol

MdeModulePkg/SdMmcPciHcDxe: Add UhsSignaling to SdMmcOverride protocol

Some SD Host Controllers use different values in Host Control 2 Register
to select UHS Mode. This patch adds a new UhsSignaling type routine to
the NotifyPhase of the SdMmcOverride protocol.

UHS signaling configuration is moved to a common, default routine
(SdMmcHcUhsSignaling). After it is executed, the protocol producer
can override the values if needed.

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Marcin Wojtas <mw@semihalf.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Hao Wu <hao.a.wu@intel.com>