INT 10 - VIDEO - ALTERNATE FUNCTION SELECT (VGA) - SELECT VERTICAL RESOLUTION

	AH = 12h
	BL = 30h
	AL = vertical resolution
	     00h 200 scan lines
	     01h 350 scan lines
	     02h 400 scan lines
Return: AL = 12h if function supported
Desc:	specify the number of scan lines used to display text modes
Note:	the specified resolution will take effect on the next mode set
SeeAlso: AH=00h