MdeModulePkg/SdMmcPciHcDxe: Hook SwitchClockFreq after SD clock start

MdeModulePkg/SdMmcPciHcDxe: Hook SwitchClockFreq after SD clock start

For eMMC modules we used to notify the platform about frequency
change only after sending CMD13 which meant that platform
might not get a chance to apply required post frequency
change fixes to get the clock stable. To fix this
notification has been moved to SdMmcHcClockSupply function
just after we start the SD clock. During first time setup
the notification won't be sent to avoid changing old behavior.

Cc: Hao A Wu <hao.a.wu@intel.com>
Cc: Marcin Wojtas <mw@semihalf.com>
Cc: Zhichao Gao <zhichao.gao@intel.com>
Cc: Liming Gao <liming.gao@intel.com>
Signed-off-by: Mateusz Albecki <mateusz.albecki@intel.com>
Tested-by: Marcin Wojtas <mw@semihalf.com>
Tested-by: Hao A Wu <hao.a.wu@intel.com>
Reviewed-by: Hao A Wu <hao.a.wu@intel.com>