Merge branch 'bugfix/fix_wifi_dbg_link_error' into 'master'

wifi: fix wifi link error when enable wifi debug

See merge request sdk/ESP8266_RTOS_SDK!1057

Author: donghengqaz

components/esp8266/linker.lf

@@ -1,7 +1,14 @@
 [mapping:pp]
 archive: libpp.a
 entries:
-    * (noflash_text)
+    if ESP8266_WIFI_DEBUG_LOG_ENABLE = n:
+        * (noflash_text)
+
+[mapping:pp_dbg]
+archive: libpp_dbg.a
+entries:
+    if ESP8266_WIFI_DEBUG_LOG_ENABLE = y:
+        * (noflash_text)
 
 [mapping:phy]
 archive: libphy.a