MAINTAINERS: update maintainer for Microsoft MANA RDMA driver

Ajay is no longer working on the MANA RDMA driver.

Konstantin Taranov has made significant contributions to implementing RC
QP in both kernel and user-mode.

He will take the responsibility of fixing bugs, reviewing patches and
developing new features for MANA RDMA driver.

Signed-off-by: Long Li <longli@microsoft.com>
Link: https://patch.msgid.link/1738964792-21140-1-git-send-email-longli@linuxonhyperv.com


Signed-off-by: Leon Romanovsky <leon@kernel.org>