INT 13 - QUICKCACHE II v4.20 - SET BUFFERED WRITES

	AH = 2Ch
	AL = new state (00h disabled, 01h enabled)
Return: AX = status (0000h successful)
Desc:	specify whether the cache should delay disk writes
Note:	this function enables or disables delayed writes for all drives; use
	  AH=38h to change a single drive
SeeAlso: AH=25h"QUICKCACHE",AH=2Dh,AH=2Eh,AH=38h