libbladeRF: Minor formatting touchup, GCC 4.8 warning workaround

GCC 4.8.1 and 4.8.2 appear to incorrectly warn about a possible
uninitialized variable. module doesn't change, so the lna_gain and
rxvga2 should always have a value when we write them on 2197 and 2207.
libbladeRF: [WIP] Removed bladerf_* calls from sync code
libbladeRF: [WIP] Removed ENABLE_LIBBLADERF_SYNC remnants
libbladeRF: [WIP] Use MUTEX macros to allow for lock checks