qt.pro: change qtfeedback dependency on qtmultimedia to optional.

qtfeeback currently has a hard dependency on qtmultimedia. qtfeedback
only uses multimedia in the mmk plugin. This change modifies the build
system only as all the required infrastructure changes in qtfeedback
are already present.

Change-Id: Ie9884dfd51fb040cde3e29247f1f51ea7f0bd637
Reviewed-by: Rohan McGovern <rohan.mcgovern@nokia.com>
Reviewed-by: Sergio Ahumada <sergio.ahumada@nokia.com>

qt.pro

@@ -82,7 +82,7 @@ module_qtmultimedia.depends = module_qtbase module_qtdeclarative
 
 module_qtfeedback.subdir = qtfeedback
 module_qtfeedback.target = module-qtfeedback
-module_qtfeedback.depends = module_qtbase module_qtmultimedia module_qtdeclarative
+module_qtfeedback.depends = module_qtbase module_qtdeclarative
 
 module_qt3d.subdir = qt3d
 module_qt3d.target = module-qt3d
@@ -158,7 +158,10 @@ exists(qtsystems/qtsystems.pro) {
     module_qtlocation.depends += module_qtsystems
 }
 exists(qtphonon/qtphonon.pro): SUBDIRS += module_qtphonon
-exists(qtmultimedia/qtmultimedia.pro): SUBDIRS += module_qtmultimedia
+exists(qtmultimedia/qtmultimedia.pro) {
+    SUBDIRS += module_qtmultimedia
+    module_qtfeedback.depends += module_qtmultimedia
+}
 exists(qtfeedback/qtfeedback.pro): SUBDIRS += module_qtfeedback
 exists(qtdocgallery/qtdocgallery.pro): SUBDIRS += module_qtdocgallery
 exists(qtpim/qtpim.pro): SUBDIRS += module_qtpim