Removed prefix to match AsmRelocateApMailBoxLoopStart

This fixes a compilation issue.

Cc: Ard Biesheuvel <[email protected]>
Cc: Jiewen Yao <[email protected]>
Cc: Jordan Justen <[email protected]>
Cc: Gerd Hoffmann <[email protected]>
Signed-off-by: Jehl Theo <[email protected]>
Reviewed-by: Jiewen Yao <[email protected]>
Reviewed-by: Rebecca Cran <[email protected]>
Tested-by: Rebecca Cran <[email protected]>

Create tag for UDK2017 release