- Honer MK_KERBEROS for Heimdal rc.d scripts.
- Add rc.c/kerberos to OLD_FILES.


git-svn-id: svn+ssh://svn.freebsd.org/base/head@273285 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f
Only build the ARM tranpoline when KERNPHYSADDR is defined as it is
otherwise unneeded in armv6 kernels.

MFC after:	1 week


git-svn-id: svn+ssh://svn.freebsd.org/base/head@273287 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f