ensure txeq changes get applied through port_settings_apply

[rcgoodfellow]

Fixes

• port_settings_apply does not update tx-eq settings #135

This PR makes two logical changes.

• Sets tx_eq_plumbed to false if a port_settings_apply call changes tx equalization settings.
• Bounces the link in the link reconciler if tx equalization needs to be plumbed on an enabled link (changes will not be picked up otherwise).

[rcgoodfellow]

Testing on berlin shows the repro steps in #135 no longer present the issue.

Applying settings.

root@oxz_switch1:~# ./swadm link apply --link qsfp11/0 --tag muffins --speed 100g --fec rs
root@oxz_switch1:~# ./swadm link sd get tx-eq qsfp11/0
           lane 0     lane 1     lane 2     lane 3
pre2      0 (  0)    0 (  0)    0 (  0)    0 (  0)
pre1      0 (  0)    0 (  0)    0 (  0)    0 (  0)
main     26 ( 26)   26 ( 26)   26 ( 26)   26 ( 26)
post1     0 (  0)    0 (  0)    0 (  0)    0 (  0)
post2     0 (  0)    0 (  0)    0 (  0)    0 (  0)

Changing settings and seeing that the link is down.

root@oxz_switch1:~# ./swadm link apply --link qsfp11/0 --tag muffins --speed 100g --fec rs --main 7
root@oxz_switch1:~# ./swadm link sd get tx-eq qsfp11/0
           lane 0     lane 1     lane 2     lane 3
pre2      0 (  0)    0 (  0)    0 (  0)    0 (  0)
pre1      0 (  0)    0 (  0)    0 (  0)    0 (  0)
main      7 (  7)    7 (  7)    7 (  7)    7 (  7)
post1     0 (  0)    0 (  0)    0 (  0)    0 (  0)
post2     0 (  0)    0 (  0)    0 (  0)    0 (  0)
root@oxz_switch1:~# ./swadm link get qsfp11/0
Port/Link  Media    Speed  FEC  Autoneg  Enabled  State  MAC
qsfp11/0   Optical  100G   RS   false    true     Down   a8:40:25:05:1f:4f

Changing settings back and showing that the link is up.

root@oxz_switch1:~# ./swadm link apply --link qsfp11/0 --tag muffins --speed 100g --fec rs
root@oxz_switch1:~# ./swadm link sd get tx-eq qsfp11/0
           lane 0     lane 1     lane 2     lane 3
pre2      0 (  0)    0 (  0)    0 (  0)    0 (  0)
pre1      0 (  0)    0 (  0)    0 (  0)    0 (  0)
main     26 ( 26)   26 ( 26)   26 ( 26)   26 ( 26)
post1     0 (  0)    0 (  0)    0 (  0)    0 (  0)
post2     0 (  0)    0 (  0)    0 (  0)    0 (  0)
root@oxz_switch1:~# ./swadm link get qsfp11/0
Port/Link  Media    Speed  FEC  Autoneg  Enabled  State  MAC
qsfp11/0   Optical  100G   RS   false    true     Up     a8:40:25:05:1f:4f