Added the test case of using multiple softdep for a module

Added the test case of using multiple softdep for a module

We defined two modules mod-softdep-a and mod-softdep-b. The softdep
statements are split into two separate modprobe configure files.

The unit test case is supposed to fail, since the libkmod will take
only the first softdep statement based on the current implementation.

Co-developed-by: Dan He <dan.h.he@intel.com>
Signed-off-by: Dan He <dan.h.he@intel.com>
Co-developed-by: Gongjun Song <gongjun.song@intel.com>
Signed-off-by: Gongjun Song <gongjun.song@intel.com>
Signed-off-by: Yuchi Chen <yuchi.chen@intel.com>
Signed-off-by: Wenjie Wang <wenjie2.wang@intel.com>
Signed-off-by: Qingqing Li <qingqing.li@intel.com>
Link: https://github.com/kmod-project/kmod/pull/311
Signed-off-by: Lucas De Marchi <lucas.de.marchi@gmail.com>