Explicitly test to see if bitmask value is non-zero.

The clang-tidy "implicit boolean conversion" check pointed out a
couple of places where masks are applied to bitfields, and then the
resulting value is implicitly tested to see if it is non-zero.  Make
these tests explicit.

https://clang.llvm.org/extra/clang-tidy/checks/readability-implicit-bool-conversion.html

mythtv/libs/libmyth/audio/audiooutputsettings.h

@@ -88,25 +88,25 @@ class MPUBLIC AudioOutputSettings
              * - FEATURE_DTSHD
              */
         bool canFeature(DigitalFeature arg)
-        { return m_features & arg; };
+        { return (m_features & arg) != 0U; };
         bool canFeature(unsigned int arg)
-        { return m_features & arg; };
+        { return (m_features & arg) != 0U; };
 
             /**
              * return true if device can or may support AC3
              * (deprecated, see canFeature())
              */
-        bool canAC3()                   { return m_features & FEATURE_AC3; };
+        bool canAC3()                   { return canFeature(FEATURE_AC3); };
             /**
              * return true if device can or may support DTS
              * (deprecated, see canFeature())
              */
-        bool canDTS()                   { return m_features & FEATURE_DTS; };
+        bool canDTS()                   { return canFeature(FEATURE_DTS); };
             /**
              * return true if device supports multichannels PCM
              * (deprecated, see canFeature())
              */
-        bool canLPCM()                  { return m_features & FEATURE_LPCM; };
+        bool canLPCM()                  { return canFeature(FEATURE_LPCM); };
             /**
              * return true if class instance is marked invalid.
              * if true, you can not assume any of the other method returned