CMakeLists: Use target_compile_definitions instead of add_definitions to...

CMakeLists: Use target_compile_definitions instead of add_definitions to define YUZU_ENABLE_COMPATIBILITY_REPORTING

Keeps the definition constrained to the yuzu target and prevents
polluting anything else in the same directory (should that ever happen).
It also keeps it consistent with how the USE_DISCORD_PRESENCE definition
is introduced below it.