Note you can't use resource governor on the reporting service itself, only connections to the database.
So report rendering/processing etc will be ungoverned.
It's also not instance aware so you might not get the results you expect.
If possible, I'd create a VM on the big host server and install reporting services on that. At least you can limit the CPU then.
Of course, if it's only lightly used then probably not an issue :-)
Like happycat, I can't see how this fixes a licensing issue if SQL remains on the second box.