llvm: Fixed remaining warnings for llvm

This commit addresses warnings emitted from the llvm
compilers which were not encountered with gnu.

Signed-off-by: Noel Eck <noel.eck@intel.com>

src/ili9341/ili9341.hpp

@@ -330,8 +330,6 @@ namespace upm {
             mraa::Result rstLow();
 
         private:
-            uint8_t     m_spiBuffer[32];
-
             mraa::Gpio  m_csLCDPinCtx;
             mraa::Gpio  m_csSDPinCtx;
             mraa::Gpio  m_dcPinCtx;