EmbeddedPkg/PrePiLib: Fixed incorrect type casting

A pointer on a UINTN variable was used instead of UINT32 one.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Andrew Fish <afish@apple.com>



git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@15252 6f19259b-4bc3-4df7-8a09-765794883524