INT 62 u - FGDRIVER v4.02 - "FG_PCXMODE" - GET OPTIMAL VIDEO MODE FOR DISPLAY
	AX = 008Bh
	ES:BX -> PCX header (see AX=008Ah)
Return: AX = optimal video mode for PCX file
	    FFFEh not a valid PCX header
	    FFFFh unable to determine compatible video mode
Note:	the FGDRIVER functions are rearranged with each major release, but
	  their parameters do not change (see #03474 at AX=0000h)
SeeAlso: AX=008Ah,AX=00B9h