Revert "NetworkProtocol: Support NetworkSuppliedServers property"

This reverts commit 525fc072.
As discussed in discord,
https://gerrit.openbmc.org/c/openbmc/openbmc/+/57931 is a legit fail.

[1] https://discord.com/channels/775381525260664832/776550056391606352/1030497797121777768



The validator is failing due to:
ERROR - NetworkSuppliedServers not defined in Complex
NTPManagerNetworkProtocol.v1_2_0.NTPProtocol (check version, spelling
and casing)

Since the bmcweb bump merged, seeing validator fails in openbmc/openbmc.

Revert, get the validator passing again,  will open an issue with
redfish since this looks like an issue with the schema itself.

Tested: None.
Change-Id: Ie8046c93eaf2f69c71eb5162dacb961032f9366c
Signed-off-by: Gunnar Mills <gmills@us.ibm.com>