MAINTAINERS: update SCTP maintainers

Vlad has stepped away from SCTP related duties.
Move him to CREDITS and add Xin Long.

Subsystem SCTP PROTOCOL
  Changes 237 / 629 (37%)
  Last activity: 2022-12-12
  Vlad Yasevich <vyasevich@gmail.com>:
  Neil Horman <nhorman@tuxdriver.com>:
    Author 20a785aa 2020-05-19 00:00:00 4
    Tags 20a785aa 2020-05-19 00:00:00 84
  Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>:
    Author 557fb586 2021-07-28 00:00:00 41
    Tags da05cecc 2022-12-12 00:00:00 197
  Top reviewers:
    [15]: lucien.xin@gmail.com
  INACTIVE MAINTAINER Vlad Yasevich <vyasevich@gmail.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

CREDITS

@@ -4183,6 +4183,10 @@ S: B-1206 Jingmao Guojigongyu
 S: 16 Baliqiao Nanjie, Beijing 101100
 S: People's Repulic of China
 
+N: Vlad Yasevich
+E: vyasevich@gmail.com
+D: SCTP protocol maintainer.
+
 N: Aviad Yehezkel
 E: aviadye@nvidia.com
 D: Kernel TLS implementation and offload support.

MAINTAINERS

@@ -18679,9 +18679,9 @@ F:	drivers/target/
 F:	include/target/
 
 SCTP PROTOCOL
-M:	Vlad Yasevich <vyasevich@gmail.com>
 M:	Neil Horman <nhorman@tuxdriver.com>
 M:	Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
+M:	Xin Long <lucien.xin@gmail.com>
 L:	linux-sctp@vger.kernel.org
 S:	Maintained
 W:	http://lksctp.sourceforge.net