dracut: let module handling function accept optional path option
    
    Let the caller pass in the module path instead of try to find the module
    path everytime. This helps optimize the overall runtime.
    
    Test results (3 rounds) on Fedora 30 in KVM VM with 8 CPUs, 2G memory, HDD:
    
        $ time ./dracut.sh --local --quiet --hostonly --hostonly-cmdline --hostonly-i18n --hostonly-mode 'strict' -o 'plymouth dash resume ifcfg' --mount '/dev/mapper/fedora-root /sysroot xfs defaults' --no-hostonly-default-device -f initramfs.img
        Before the commit:
        real    0m11.782s  |  real    0m11.505s  |  real    0m11.958s
        user    0m9.169s   |  user    0m9.218s   |  user    0m9.327s
        sys     0m10.839s  |  sys     0m10.829s  |  sys     0m10.925s
    
        After this commit:
        real    0m9.866s  |  real    0m9.580s  |  real    0m9.638s
        user    0m9.048s  |  user    0m9.142s  |  user    0m9.120s
        sys     0m7.411s  |  sys     0m7.775s  |  sys     0m7.745s
    
    Test result of building a ordinary image:
    
        $ time ./dracut.sh --local --quiet -f initramfs.img
        Before the commit:
        real    0m34.697s  |  real    0m34.371s  |  real    0m35.122s
        user    0m27.608s  |  user    0m27.524s  |  user    0m27.705s
        sys     0m22.341s  |  sys     0m22.032s  |  sys     0m22.246s
    
        After the commit:
        real    0m31.914s  |  real    0m31.006  |  real    0m31.289ss
        user    0m27.315s  |  user    0m27.324  |  user    0m27.290ss
        sys     0m19.051s  |  sys     0m18.916  |  sys     0m19.022ss
    
    This will have an ~2s speed up.
    
    Signed-off-by: Kairui Song <kasong@redhat.com>
    (cherry picked from commit 5916d31b24ad9eb21fd376929a96c459813315a1)
    
    Cherry-picked from: 5916d31b
    Resolves: #1734047
    
    patch_name: 0021.patch
    present_in_specfile: true
    location_in_specfile: 21
    squash_commits: true