docs(maintainers): update LTS maintainers

Updating LTS maintainers list as agreed with other LTS
maintainers.

Change-Id: Ibf087c6b0e24d6faa9dafb6f8a0955a47f583f28
Signed-off-by: Govindraj Raja <govindraj.raja@arm.com>
(cherry picked from commit 52e5a3f1e20d2665a1f033fd2118d73c6bb5f0e5)
1 file changed