doc: remove additional incorrect information about Maintenance mode

Refs: nodejs#405 (comment)

README.md

@@ -80,7 +80,7 @@ major version transitions to the Long Term Support plan.
 
 Every major version covered by the LTS plan will be actively maintained for a
 period of 18 months from the date it enters LTS coverage. Following those 18
-months of active support, the major version will transition into "maintenance"
+months of active support, the major version will transition into Maintenance
 mode for 12 additional months.
 
 The exact date that a release stream will be moved to LTS, moved between LTS
@@ -98,12 +98,6 @@ Generally changes are expected to live in a *Current* release for at least 2
 weeks before being backported. It is possible for a commit to land earlier at
 the discretion of the Release working group and the maintainers of the LTS branches.
 
-Once a release moves into Maintenance mode, only ***critical*** bugs,
-***critical*** security fixes, documentation updates, and updates to ensure
-consistency and usability of the N-API across LTS releases will be permitted.
-Unless a change is ***urgent*** it will be planned into a release once per
-quarter. Such releases will only be made when necessary.
-
 Note that while it is possible that critical security and bug fixes may lead to
 *semver-major* changes landing within an LTS stream, such situations will be
 rare and will land as *semver-minor* bumps in the LTS covered version.