I'm not aware of a feat, however with some skills.2da tweaking you can make any class use any skill without penalty.
Not exactly "fair" seeing as you're not spending a feat for the benefit, however it's a simple method for achieving what you want
Below is an edited skills.2da that will enable all classes to use any skill as a cross-class. Keep in mind, if you already have a skills.2da in your override, this will overwrite it.
If you want to edit your own, just change any " 0 "'s to " 1 "'s in the columns with a "_class" suffix