INT 21 - Phar Lap 386/DOS-Extender - RELEASE MS-DOS MEMORY BLOCK

	AX = 25C1h
	CX = real-mode paragraph address of memory block to free
Return: CF clear if successful
	    EAX destroyed
	CF set on error
	    AX = error code
		07h MS-DOS memory control blocks destroyed
		09h invalid memory block address in CX
SeeAlso: AX=25C0h,AX=25C2h