dt-bindings: reset: rtd1295: Add SB2 reset

Add a constant for reset3 SB2, based on downstream crt_sys_reg.h.
Acked-by: Rob Herring <robh@kernel.org>
Acked-by: James Tai <james.tai@realtek.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>

include/dt-bindings/reset/realtek,rtd1295.h

@@ -75,6 +75,9 @@
 #define RTD1295_RSTN_CBUS_TX		30
 #define RTD1295_RSTN_SDS_PHY		31
 
+/* soft reset 3 */
+#define RTD1295_RSTN_SB2		0
+
 /* soft reset 4 */
 #define RTD1295_RSTN_DCPHY_CRT		0
 #define RTD1295_RSTN_DCPHY_ALERT_RX	1