MdeModulePkg/EbcDxe: Mitigate memcpy intrinsics

MdeModulePkg/EbcDxe: Mitigate memcpy intrinsics

Assignments of structure values cause the emission of memcpy()
intrinsics by the CLANG38 toolchain. Substitute the assignments with
calls to CopyMem() to mitigate the issue.

Cc: Jian J Wang <jian.j.wang@intel.com>
Cc: Hao A Wu <hao.a.wu@intel.com>
Cc: Vitaly Cheptsov <vit9696@protonmail.com>
Signed-off-by: Marvin H?user <mhaeuser@posteo.de>
Reviewed-by: Hao A Wu <hao.a.wu@intel.com>