lib, zebra: Minimize display of link-params sub data

lib, zebra: Minimize display of link-params sub data

When link-params is configured it auto starts displaying
6000-02# conf t
dell-s6000-02(config)# int swp1
dell-s6000-02(config-if)# link-params
dell-s6000-02(config-link-params)# admin-grp 0x12345678
dell-s6000-02(config-link-params)# end
dell-s6000-02# show run

interface swp1
 link-params
  enable
  metric 0              <----Remove the bw lines
  max-bw 1.25e+06
  max-rsv-bw 1.25e+06
  unrsv-bw 0 1.25e+06
  unrsv-bw 1 1.25e+06
  unrsv-bw 2 1.25e+06
  unrsv-bw 3 1.25e+06
  unrsv-bw 4 1.25e+06
  unrsv-bw 5 1.25e+06
  unrsv-bw 6 1.25e+06
  unrsv-bw 7 1.25e+06
  admin-grp 305419896
  exit-link-params
!

I'd like to reduce this to:

interface enp0s3
 ip igmp
 ip pim sm
 link-params
  enable
  admin-grp 0x12345678    <----- Fix this to be what we entered
  exit-link-params
!

Signed-off-by: Donald Sharp <sharpd@cumulusnetworks.com>
Signed-off-by: David Lamparter <equinox@opensourcerouting.org>