INT 62 u - FGDRIVER v4.02 - "FG_VBFREE" - RELEASE VIRTUAL BUFFER
	AX = 00D2h
	BX = virtual buffer handle
Notes:	the FGDRIVER functions are rearranged with each major release, but
	  their parameters do not change (see #03474)
	this function should be used only for buffers created with FG_VBALLOC
SeeAlso: AX=00CDh,AX=00D4h,AX=00D5h