MdeModulePkg/SdMmcPciHcDxe: Refactor data transfer completion

MdeModulePkg/SdMmcPciHcDxe: Refactor data transfer completion

This patch refactors the way in which the driver will check
the data transfer completion. Data transfer related
functionalities have been moved to separate function.

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: Hao A Wu <hao.a.wu@intel.com>
Reviewed-by: Hao A Wu <hao.a.wu@intel.com>