MdeModulePkg/SmmCorePerformanceLib: Remove offset from comm buffer dest space

A check validates that if perf records are being written to the comm
buffer (not a buffer pointed to from the comm buffer) that enough
space is available after the `SMM_BOOT_RECORD_COMMUNICATE` header in
the comm buffer for the boot record size requested. That check
currently removes the offset from the boot record size but that is
not needed since the offset is applied to the source buffer and the
record size is what is copied into the desintation (comm buffer).

Signed-off-by: Michael Kubacki <[email protected]>

Author: makubacki

MdeModulePkg/Library/SmmCorePerformanceLib/MmCorePerformanceLib.c

@@ -877,7 +877,7 @@ FpdtSmiHandler (
       }
 
       // Note: Comm size passed to this handler already has OFFSET_OF (EFI_MM_COMMUNICATE_HEADER, Data) removed.
-      if ((SmmCommData->BootRecordData == NULL) && (BootRecordSize - BootRecordOffset > TempCommBufferSize - sizeof (SMM_BOOT_RECORD_COMMUNICATE))) {
+      if ((SmmCommData->BootRecordData == NULL) && (BootRecordSize > TempCommBufferSize - sizeof (SMM_BOOT_RECORD_COMMUNICATE))) {
         Status = EFI_BUFFER_TOO_SMALL;
         break;
       }