genoffsets: Remove constexpr on PORT_OFFSETS array

Not sure why CLang doesn't allow this to be constexpr while GCC does,
let's figure out later why this is the case.

Error message:

   src/dynports.cc:13:45: error: constexpr variable cannot have
       non-literal type 'const std::array<uint16_t, 4576>' (aka 'const
       array<unsigned short, 4576>')
   static constexpr std::array<uint16_t, 4576> PORT_OFFSETS {{
                                               ^

Signed-off-by: aszlig <[email protected]>

scripts/genoffsets.py

@@ -28,7 +28,7 @@
         formatted = [', '.join(['{:>5}'.format(o) for o in chunk])
                      for chunk in chunks]
 
-        sig = 'static constexpr std::array<uint16_t, {}> PORT_OFFSETS'
+        sig = 'static std::array<uint16_t, {}> PORT_OFFSETS'
         header = sig.format(len(offsets)) + ' {{\n    '
         out = header + ',\n    '.join(formatted) + '\n}};\n'