Remove patch(1) from the list of bootstrap tools.

Remove patch(1) from the list of bootstrap tools.

Now that we no longer ship patches in the tree, patch(1) is no longer
needed during buildworld, buildkernel etc. The last patch was removed
in d8d77baac2714febf36f4ac37afccbbbdcdc8857.

While here, also remove our old bsd.patch.mk which was used in the
old days to handle local changes to contrib/ code using patches we
shipped. Since we have git, we use vendor branches which we merge and
then just modify on master for this purpose.