INT 10 - VESA SuperVGA BIOS v1.2+ - GET/SET DAC PALETTE CONTROL

	AX = 4F08h
	BL = subfunction
	    00h set DAC palette width
		BH = desired number of bits per primary color
	    01h get DAC palette width
Return: AL = 4Fh if function supported
	AH = status
	    00h successful
		BH = current number of bits per primary (06h = standard VGA)
	    01h failed