RBIL61 - INT 10 - VIDEO - AX PC - GET/SET SCROLL MODE

INT 10 - VIDEO - AX PCIBM PC - GET/SET SCROLL MODE
	AX = 8200h
	BL = new scroll mode or FFh to get current mode
	    00h dynamic, 01h software
Return: AL = scroll mode (current mode if BL=FFh, previous mode otherwise)
SeeAlso: AH=06h,AH=07h