build: Add missing dependencies when building param SWIG interfaces
build: Add missing dependencies when building param SWIG interfaces

This patch adds an explicit dependency between param_%s.i and the
Python source file defining the object. Previously, the build system
didn't rebuild SWIG interfaces correctly when an object's Python
sources were updated.

haowu4682/gem5,LingxiaoJIA/gem5,haowu4682/gem5,haowu4682/gem5,haowu4682/gem5,LingxiaoJIA/gem5,LingxiaoJIA/gem5,haowu4682/gem5,haowu4682/gem5,LingxiaoJIA/gem5,haowu4682/gem5,haowu4682/gem5,LingxiaoJIA/gem5,LingxiaoJIA/gem5,haowu4682/gem5,LingxiaoJIA/gem5