cmake: remove pluginssrv link

we can use the same plugins folder on add_subdirectory() if we add
the binary dir.

CMakeLists.txt

@@ -319,14 +319,14 @@ add_subdirectory(devices)
 
 if (BUILD_GUI)
     add_subdirectory(sdrgui)
-    add_subdirectory(plugins)
+    add_subdirectory(plugins plugins)
 endif()
 
 if (BUILD_SERVER)
     add_subdirectory(sdrsrv)
     set(SERVER_MODE ON)
     add_definitions(-DSERVER_MODE)
-    add_subdirectory(pluginssrv)
+    add_subdirectory(plugins pluginssrv)
     remove_definitions(-DSERVER_MODE)
     set(SERVER_MODE OFF)
 endif()

pluginssrv

@@ -1 +0,0 @@
-plugins