fix implicit conversion from wxString to const char*
fix implicit conversion from wxString to const char*

it is completely unnecessary and can cause compilation error with some wxWidgets versions

limemicro/lms7suite,limemicro/lms7suite,myriadrf/LimeSuite,myriadrf/LimeSuite,limemicro/lms7suite,myriadrf/LimeSuite,limemicro/lms7suite,limemicro/lms7suite,myriadrf/LimeSuite,myriadrf/LimeSuite