rtl_nic: add firmware files for RTL8153

This adds the firmware for Realtek RTL8153 Based USB Ethernet Adapters.

1. Fix compatible issue for Asmedia hub.
2. Fix compatible issue for Compal platform.
3. Fix sometimes the device is lost after rebooting.
4. Improve the compatibility for EEE.

Signed-off-by: Hayes Wang <hayeswang@realtek.com>
Signed-off-by: Josh Boyer <jwboyer@kernel.org>

WHENCE

@@ -2968,6 +2968,17 @@ Licence:
 
 --------------------------------------------------------------------------
 
+Driver: r8152 - Realtek RTL8152/RTL8153 Based USB Ethernet Adapters
+
+File: rtl_nic/rtl8153a-2.fw
+File: rtl_nic/rtl8153a-3.fw
+File: rtl_nic/rtl8153a-4.fw
+File: rtl_nic/rtl8153b-2.fw
+
+Licence: Redistributable. See LICENCE.rtlwifi_firmware.txt for details.
+
+--------------------------------------------------------------------------
+
 Driver: vt6656 - VIA VT6656 USB wireless driver
 
 File: vntwusb.fw