Merge pull request #4353 from theotherjimmy/fix-static-nrf5

Add static to NRF5 SDK11 macro definition

Author: theotherjimmy

targets/TARGET_NORDIC/TARGET_NRF5/TARGET_SDK11/libraries/experimental_section_vars/section_vars.h

@@ -242,7 +242,7 @@
 #elif defined(__ICCARM__)
 
 #define NRF_SECTION_VARS_ADD(section_name, type_def) \
-    __root type_def @ #section_name
+    static __root type_def @ #section_name
 
 #endif