INT 2F - DESQview v2.26+ External Device Interface - DVP PROCESSING COMPLETE
        AX = DE0Bh
        BX = mapping context of DESQview system task
        CX = number of system memory paragraphs required for the use of all
                XDI drivers (DV will add this to system memory in DVP buffer)
        DX = handle of DESQview system task
        SI = mapping context of new process if it starts
        ES:DI -> DVP buffer
Return: CX incremented as needed
Notes:  once DV invokes this function, the DVP buffer contents may be changed
        driver should pass this call to previous handler before processing it