Vector extension test (vfdiv, vfmax, vfmin, vfmul) 1. Define additional operations (vfdiv, vfmax, vfmin, vfmul) 2. Fix typos in softrvv/include/softrvv_vfsub.h 3. Remove unnecessary header files in softrvv/include/softrvv_vmax.h and softrvv/include/softrvv_vmin.h 4. Add tests for newly added operations in tests/CMakeLists.txt - They are tested with "m springbok && ctest --verbose -R ... --gtest_color=yes" Change-Id: Ia84de66974f0e41b0373e112d19393a7d4ca5b0a