rtl_nic: add new firmware for RTL8153 and RTL8156 series

1. rtl8153c-1 v1 03/31/21.
2. rtl8156a-2 v1 04/15/21.
3. rtl8156b-2 v1 04/15/21.
Signed-off-by: Hayes Wang <hayeswang@realtek.com>
Signed-off-by: Josh Boyer <jwboyer@kernel.org>

WHENCE

@@ -3260,6 +3260,9 @@ File: rtl_nic/rtl8153a-2.fw
 File: rtl_nic/rtl8153a-3.fw
 File: rtl_nic/rtl8153a-4.fw
 File: rtl_nic/rtl8153b-2.fw
+File: rtl_nic/rtl8153c-1.fw
+File: rtl_nic/rtl8156a-2.fw
+File: rtl_nic/rtl8156b-2.fw
 
 Licence: Redistributable. See LICENCE.rtlwifi_firmware.txt for details.