INT 78 - TARGA.DEV - SET DMAsee Direct Memory Access CHANNEL
	AH = 02h
	AL = interface board DMAsee Direct Memory Access channel
Return: CF set on error
	AL = error code (see #03786)
Note:	if this routine is not called, the DMAsee Direct Memory Access channel is the driver's default
	  (usually 3)
SeeAlso: AH=00h,AH=03h"TARGA"