v4l2lepton: fixes cross-compilation
v4l2lepton: fixes cross-compilation

* fixes dependencies in Makefile,
* remove Lepton_I2C compilation (not used),
* make it cross-compilable

PureEngineering/LeptonModule,PureEngineering/LeptonModule,groupgets/LeptonModule,groupgets/LeptonModule,PureEngineering/LeptonModule,groupgets/LeptonModule