compiler warning (gcc 7.0.1): lfpfunc.c

OS: Fedora release 27 (Rawhide)

gcc (GCC) 7.0.1 20170425 (Red Hat 7.0.1-0.16)

(GNU libc) 2.25.90

Built at NTPsec commit on 2017-05-05: Partially revert: cfe5c712 Address GitLab issue #276 (closed): Tarball should include pre-built man pages

../../tests/libntp/lfpfunc.c: In function ‘TEST_lfpfunc_SignedRelOps_’:
../../tests/libntp/lfpfunc.c:295:4: warning: this statement may fall through [-Wimplicit-fallthrough=]
    l_fp_swap(&op1, &op2);
    ^~~~~~~~~~~~~~~~~~~~~
../../tests/libntp/lfpfunc.c:297:3: note: here
   case 1:
   ^~~~
../../tests/libntp/lfpfunc.c: In function ‘TEST_lfpfunc_UnsignedRelOps_’:
../../tests/libntp/lfpfunc.c:325:4: warning: this statement may fall through [-Wimplicit-fallthrough=]
    l_fp_swap(&op1, &op2);
    ^~~~~~~~~~~~~~~~~~~~~
../../tests/libntp/lfpfunc.c:327:3: note: here
   case 1:
   ^~~~