docs/: get rid of unneeded $(strip ..)

docs/buildroot.html

@@ -959,7 +959,7 @@ endif
     <a name="line53" id="line53">53</a> # Toplevel Makefile options
     <a name="line54" id="line54">54</a> #
     <a name="line55" id="line55">55</a> #############################################################
-    <a name="line56" id="line56">56</a> ifeq ($(strip $(BR2_PACKAGE_FOO)),y)
+    <a name="line56" id="line56">56</a> ifeq ($(BR2_PACKAGE_FOO),y)
     <a name="line57" id="line57">57</a> TARGETS+=foo
     <a name="line58" id="line58">58</a> endif