Remove -j ${NJOBS} from make invocations in the ci

According to
https://www.gnu.org/software/make/manual/html_node/Options_002fRecursion.html#Options_002fRecursion
it's not necessary, because we pass `-j ${NJOBS}` to the top-level `make`
invocation in `.travis.yml`.  Additionally, explicitly passing `-j` in,
e.g., fiat-crypto, results in error messages such as
```
make[2]: *** write jobserver: Bad file descriptor.  Stop.
make[2]: *** Waiting for unfinished jobs....
make[2]: *** write jobserver: Bad file descriptor.  Stop.
make[1]: *** [coqprime] Error 2
make[1]: INTERNAL: Exiting with 1 jobserver tokens available; should be 2!
make[1]: Leaving directory `/home/travis/build/JasonGross/coq/_build_ci/fiat-c
```
because the `-j` on the `make` in the `ci-fiat-crypto.sh` script
disables jobserver mode, and the submake in fiat-crypto to make coqprime
does not explicitly pass `-j`, and so reenables jobserver mode, and then
`make` gets very confused.

Commit made with
```bash
cd dev/ci
git grep --name-only -- 'make -j ${NJOBS}' | xargs sed s'/make -j \${NJOBS}/make/g' -i
 git grep --name-only -- 'make -f Makefile.coq -j ${NJOBS}' | xargs sed s'/make -f Makefile.coq -j \${NJOBS}/make -f Makefile.coq/g' -i
```

1 files changed, 1 insertions, 1 deletions

diff --git a/dev/ci/ci-math-comp.sh b/dev/ci/ci-math-comp.sh
index bb8188da4..701403f2c 100755
--- a/dev/ci/ci-math-comp.sh
+++ b/dev/ci/ci-math-comp.sh
@@ -12,4 +12,4 @@ checkout_mathcomp ${mathcomp_CI_DIR}
 ( cd ${mathcomp_CI_DIR}/mathcomp                  && \
   sed -i.bak '/PFsection/d'                  Make && \
   sed -i.bak '/stripped_odd_order_theorem/d' Make && \
-  make Makefile.coq && make -f Makefile.coq -j ${NJOBS} all )
+  make Makefile.coq && make -f Makefile.coq all )