edk2: QcomModulePkg: Remove extra addition of DtbSize for Header Version 2

In the case where device with a bootimage having header version 2 is
booting in recovery mode, the dtb size was getting added twice to the
ImageSizeActual variable which is used to read data from the flash.
To avoid reading unnecessary bytes, remove the extra addition.

Change-Id: I274fccfc301b28c530346af7745429f36447055a
1 file changed