ath79-generic: add support for TP-Link Archer A7 v5

This patch was requested from a community member and has been taken from
eulenfunk:
https://github.com/eulenfunk/firmware/blob/2020.2.x/patches/add-TPlinkArcherA7V5.patch

targets/ath79-generic

@@ -95,6 +95,10 @@ device('tp-link-archer-c2-v3', 'tplink_archer-c2-v3', {
 
 })
 
+device('tp-link-archer-a7-v5', 'tplink_archer-a7-v5', {
+       packages = ATH10K_PACKAGES_QCA9888,
+})
+
 device('tp-link-archer-c6-v2', 'tplink_archer-c6-v2', {
 	packages = ATH10K_PACKAGES_QCA9888,
 })