Removed prefix to match AsmRelocateApMailBoxLoopStart

This fixes a compilation issue.

Cc: Ard Biesheuvel <ardb+tianocore@kernel.org>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Jehl Theo <theojehl76@gmail.com>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>
Reviewed-by: Rebecca Cran <quic_rcran@quicinc.com>
Tested-by: Rebecca Cran <quic_rcran@quicinc.com>

OvmfPkg/TdxDxe/X64/ApRunLoop.nasm

@@ -83,7 +83,7 @@ AsmRelocateApMailBoxLoopEnd:
 ;-------------------------------------------------------------------------------------
 global ASM_PFX(AsmGetRelocationMap)
 ASM_PFX(AsmGetRelocationMap):
-    lea        rax, [ASM_PFX(AsmRelocateApMailBoxLoopStart)]
+    lea        rax, [AsmRelocateApMailBoxLoopStart]
     mov        qword [rcx], rax
     mov        qword [rcx +  8h], AsmRelocateApMailBoxLoopEnd - AsmRelocateApMailBoxLoopStart
     ret