asmjit: update build integration

[scribam]

• ASMJIT_STATIC is automatically defined when ASMJIT_EMBED is set:
  • https://github.com/asmjit/asmjit/blob/673dcefaa048c5f5a2bf8b85daf8f7b9978d018a/src/asmjit/asmjit_build.h#L90-93)
  • https://github.com/asmjit/asmjit/blob/master/CMakeLists.txt#L13-L15
• Remove paths based on the ${RPCS3_SRC_DIR} variable
• Minor changes for system ffmpeg cmake integration
• fix compiler warning "-Winconsistent-missing-override"

[kd-11]

In future if possible lump the submodule updates in one PR (separate commits of course) otherwise its a chore to merge these.

[scribam]

No submodule updates on this one :) but I get your point, I will keep it in mind.
However, I will be interested to know more about how the core team proceeds with reviews and merges, and if there is anything the contributors can do to speed up these processes.

[kd-11]

Well, if youre updating build integration for example, have it all in one place. You can mark it as WIP while you add more parts to it. Merging will happen one PR at a time, likely with some time in between (you have to start a new build after every merge as the PRs become outdated after each merging). As for review, things like build integration aren't too critical as they do not actually change emulator functionality. For emulation changes, provide ps3 tests proving the commits are correct and it can get merged in minutes.