rtl_nic: add firmware for RTL8125B

This adds firmware for RTL8125B rev.a and RTL8125B rev.b.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Chunhao Lin <hau@realtek.com>
Signed-off-by: Josh Boyer <jwboyer@kernel.org>

WHENCE

@@ -3060,6 +3060,12 @@ Version: 0.0.2
 File: rtl_nic/rtl8125a-3.fw
 Version: 0.0.1
 
+File: rtl_nic/rtl8125b-1.fw
+Version: 0.0.1
+
+File: rtl_nic/rtl8125b-2.fw
+Version: 0.0.1
+
 Licence:
  * Copyright © 2011-2013, Realtek Semiconductor Corporation
  *