AY38910: Fix issue with interrupt handling

Source/HBIOS/ay38910.asm

@@ -159,14 +159,16 @@ AY_TIMER:
 	LD	(AY_TIMTIK), A
 	JR	NZ, AY_TIMER1
 
-	LD	HL, (AY_TIMHOOK)	; REMOVE US FROM THE TIMER HOOKS LIST
-	LD	(VEC_TICK + 1), HL
-
 	LD	E,$00			; SET VOLUME OFF
 	CALL	AY_SETV			; ON ALL CHANNELS
 	LD	A, $01			; READY & NOT IN INTERUPT HANDLER
 	LD	(AY_READY), A
 
+	LD	DE, AY_TIMER		; MAKE AY_TIMER A NO_OP HANDLER
+	LD	HL, AY_TIMER1
+	LD	BC, 3
+	LDIR
+
 AY_TIMER1:
 	JP	0			; OVERWRITTEN WITH NEXT HANDLER
 AY_TIMHOOK:	.EQU	$ - 2