3ds: Minor Makefile changes
- Fix the macOS check so that it only includes the linker command line and not the whole block
- Remove a dash from the .map file name, likely a typo
- Don't remove the .elf file after packaging, so that it can be used to debug any issues with the build
Change-Id: I9639263169e027c9702ac617eb8209b1707e11f4