This commit adds the TSC (Technical Steering Committee) info
to the openbmc/openbmc README.

As suggested in and partially implemented in
https://gerrit.openbmc-project.xyz/c/openbmc/docs/+/28107

 the docs
README is specific to the docs repo and the openbmc/openbmc README
is for more general project information since the openbmc/openbmc
README is most likely the first landing spot of anyone new to
the project.

Change-Id: I539357bd78dbad39bda874b68a4acb587ecb5595
Signed-off-by: Gunnar Mills <gmills@us.ibm.com>