bletest: Use endian.h API for protocol data
bletest: Use endian.h API for protocol data

Don't use TOFROMLE16 API for protocol data. This API hide direction of
convertion making code hard to follow.

andrzej-kaczmarek/incubator-mynewt-core,andrzej-kaczmarek/apache-mynewt-core,IMGJulian/incubator-mynewt-core,andrzej-kaczmarek/apache-mynewt-core,mlaz/mynewt-core,mlaz/mynewt-core,andrzej-kaczmarek/incubator-mynewt-core,wes3/incubator-mynewt-core,andrzej-kaczmarek/apache-mynewt-core,IMGJulian/incubator-mynewt-core,IMGJulian/incubator-mynewt-core,wes3/incubator-mynewt-core,andrzej-kaczmarek/incubator-mynewt-core,andrzej-kaczmarek/incubator-mynewt-core,andrzej-kaczmarek/incubator-mynewt-core,wes3/incubator-mynewt-core,wes3/incubator-mynewt-core,mlaz/mynewt-core,andrzej-kaczmarek/apache-mynewt-core,mlaz/mynewt-core,mlaz/mynewt-core,wes3/incubator-mynewt-core,IMGJulian/incubator-mynewt-core,IMGJulian/incubator-mynewt-core