mtree: Remove stray atm directory

[jlduran]

Summary

ATM support for netgraph was removed in af0cc0b22362 ("NgATM: Remove
netgraph ATM support")

Remove the directory form the mtree specification.

[emaste]

Ought to list Fixes: af0cc0b22362 I think

[jlduran]

In D53260#1216709, @emaste wrote:

Ought to list Fixes: af0cc0b22362 I think

Yes, I wasn't sure either. I'll investigate. Thank you!

[jlduran]

In D53260#1216709, @emaste wrote:

Ought to list Fixes: af0cc0b22362 I think

It was actually removed in D39005.
There are a couple more stragglers, do I create a separate revision and tag @brooks?:

diff
diff --git a/share/mk/bsd.libnames.mk b/share/mk/bsd.libnames.mk
index 2f099e0579b2..b72845944542 100644
--- a/share/mk/bsd.libnames.mk
+++ b/share/mk/bsd.libnames.mk
@@ -124,7 +124,6 @@ LIBNCURSES?=        ${LIBDESTDIR}${LIBDIR_BASE}/libncurses.a
 LIBNCURSESW?=  ${LIBDESTDIR}${LIBDIR_BASE}/libncursesw.a
 LIBNETGRAPH?=  ${LIBDESTDIR}${LIBDIR_BASE}/libnetgraph.a
 LIBNETMAP?=    ${LIBDESTDIR}${LIBDIR_BASE}/libnetmap.a
-LIBNGATM?=     ${LIBDESTDIR}${LIBDIR_BASE}/libngatm.a
 LIBNV?=                ${LIBDESTDIR}${LIBDIR_BASE}/libnv.a
 LIBNVPAIR?=    ${LIBDESTDIR}${LIBDIR_BASE}/libnvpair.a
 LIBOPENCSD?=   ${LIBDESTDIR}${LIBDIR_BASE}/libopencsd.a
diff --git a/targets/pseudo/userland/lib/Makefile.depend b/targets/pseudo/userland/lib/Makefile.depend
index 63c7e69719c2..777d10c87fe8 100644
--- a/targets/pseudo/userland/lib/Makefile.depend
+++ b/targets/pseudo/userland/lib/Makefile.depend
@@ -114,7 +114,6 @@ DIRDEPS = \
        lib/libmixer \
        lib/libmp \
        lib/libnetgraph \
-       lib/libngatm \
        lib/libnv \
        lib/libpam/libpam \
        lib/libpam/modules/pam_chroot \