Minor Fix in SPK Driver and Tick Counter Space Reservation

- Fix ensures that the speaker control bit is set the same as it was initially after playing a tone.
- Reserve 2 bytes in the proxy for a platform dependent tick counter value.  Currently for HEATH platform.

Source/HBIOS/hbios.asm

@@ -993,7 +993,8 @@ HBX_BUF_END	.EQU	$
 	.DW	0			; HB_DSTADR: BNKCPY DESTINATION ADDRESS
 	.DB	BID_USR			; HB_DSTBNK: BNKCPY DESTINATION BANK ID
 	.DW	0			; HB_CPYLEN: BNKCPY LENGTH
-	.FILL	4,0			; FILLER, RESERVED FOR FUTURE HBIOS USE
+	.DW	0			; RESERVED FOR OPTIONAL TICK CTR, PLATFORM DEPENDENT
+	.DW	0			; RESERVED FOR FUTURE HBIOS USE
 	.DB	0			; SHADOW VALUE FOR RTC LATCH PORT
 	.DB	$FE			; HB_LOCK: HBIOS MUTEX LOCK
 	JP	HBX_INVOKE		; HB_INVOKE: FIXED ADR ENTRY FOR HBX_INVOKE (ALT FOR RST 08)

Source/HBIOS/spk.asm

@@ -303,6 +303,14 @@ BE_AGAIN:
 BE_END:
 	HB_EI
 	POP	IX
+;
+;	Above flow flips the speaker bit an odd number of times which
+;	leaves the bit set to the opposite value it started at.  This
+;	ensures that the bit is properly reset to its original value.
+;
+	LD	A,(HB_RTCVAL)		; Get the current RTC latch value
+	OUT	(RTCIO),A		; Set it
+;
 	RET				; ALWAYS EXITS WITH SUCCESS STATUS (A=0)
 ;
 ;======================================================================