INT 2F - DOS 5+ - QUERY FREE HMA SPACE

	AX = 4A01h
Return: BX = number of bytes available in HMA (0000h if DOS not using HMA)
	ES:DI -> start of available HMA area (FFFFh:FFFFh if not using HMA)
Notes:	called by Windows 3.1 DOSX.EXE
	supported by Novell DOS 7
SeeAlso: AX=4310h,AX=4A02h