DirectShowPlayerService::doSetVideoProbe(): Break out of loop

Fix g++ 7.1 warning:
player\directshowplayerservice.cpp:724:9: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
         if (SUCCEEDED(DirectShowUtils::connectFilters(m_graph, m_source, m_videoSampleGrabber->filter(), true)))

player\directshowplayerservice.cpp:726:13: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'
             break;

Amends 8e4d966f

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Change-Id: I491e14e0116140d2ebb870441c2f048a2d7ddc31
Reviewed-by: Christian Stromme <christian.stromme@qt.io>