interconnect: Disallow interconnect core to be built as a module

Building individual drivers as modules is fine but allowing a core framework to be built as a module makes it really complex and should be avoided. Whatever uses the interconnect core APIs must also be built as a module if interconnect core is built as module, else we will see compilation failures. If another core framework (like cpufreq, clk, etc), that can't be built as module, needs to use interconnect APIs then we will start seeing compilation failures with allmodconfig configurations as the symbols (like of_icc_get()) used in other frameworks will not be available in the built-in image. Disallow the interconnect core to be built as a module to avoid all these issues.

VKViresh Kumar committed 7 years ago