Remove dir printout for mem usage

[kennethlimcp]

Memory use: 
   text    data     bss     dec     hex filename
  72416     704   12064   85184  14cc0 /spark/compile_server/shared/workspace/worker_2/core-firmware/build/d61e499f647869a790929d5eb965d33c49251c5aab42b3274d23ecef2b72.elf

I'm suggesting to either skip the filename display or strip off the dir path and just leave the filename which is still too long.

[dmiddlecamp]

ahh sure, that's something we could drop, thanks! :)

[kennethlimcp]

@dmiddlecamp, since you are working on the buildfarm, you might want to do this?