iOS: Remove unnecessary check in IosBuildStep::init()

A buildstep always belongs to a build configuration.

Change-Id: Ia24e571fbaf47c97797661774e87d583bddb1d76
Reviewed-by: Eike Ziller <eike.ziller@qt.io>

src/plugins/ios/iosbuildstep.cpp

@@ -170,13 +170,9 @@ bool IosBuildStep::init()
     if (!AbstractProcessStep::init())
         return false;
 
-    BuildConfiguration *bc = buildConfiguration();
-
     ToolChain *tc = ToolChainKitAspect::cxxToolChain(kit());
-    if (!tc)
+    if (!tc) {
         emit addTask(Task::compilerMissingTask());
-
-    if (!bc || !tc) {
         emitFaultyConfigurationMessage();
         return false;
     }