Appease GCC's 'return-type' warning

[johnboiles]

GCC isn't smart enough that if we get to the assert the return value doesn't matter anyways and raises a control reaches end of non-void function warning. This is especially a bummer when treating warnings as errors (which I think is the ESP-IDF 4.4 default)

embedded-app/components/HULP/src/hulp.c: In function 'print_insn':
embedded-app/components/HULP/src/hulp.c:663:1: error: control reaches end of non-void function [-Werror=return-type]
 }
 ^
cc1: some warnings being treated as errors

[boarchuz]

Thanks @johnboiles, I think abort() might be better here as this is a fatal error (should never return and should be clear that it never returns)? assert(0) is definitely incorrect as its behaviour depends on the build configuration, thanks for pointing that out.

[johnboiles]

Just confirmed that also compiles fine. Works for me!