Docs: keep rules of name in the same way

Docs: keep rules of name in the same way

1. The implementation of the O2 interface is named 'INF O2 server'
2. Anywhere mentions about the O2 interface are 'O-RAN O2 interfaces'

Signed-off-by: Zhang Rong(Jon) <rong.zhang@windriver.com>
Change-Id: Ie727acec0c9d76446afb53dfe4261529a01e8777
(cherry picked from commit 5affabd057a01b9aaa4c7354e950753a8898954c)