StdLib: Fix parameter type errors.

Fix casts of parameters to sprintf() so that they have the correct type.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by:  Stefan Kaeser <stefankaeser@hotmail.com>
Reviewed-by:  daryl.mcdaniel@intel.com



git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@16125 6f19259b-4bc3-4df7-8a09-765794883524