MAINTAINERS: Clean RXE section and add Zhu as RXE maintainer

Zhu Yanjun contributed many patches to RXE and expressed genuine interest
in improve RXE even more. Let's add him as a maintainer.

Link: https://lore.kernel.org/r/20200312083658.29603-1-leon@kernel.org
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Acked-by: Moni Shoua <monis@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

Author: Leon Romanovsky

MAINTAINERS

@@ -15419,11 +15419,9 @@ F:	drivers/infiniband/sw/siw/
 F:	include/uapi/rdma/siw-abi.h
 
 SOFT-ROCE DRIVER (rxe)
-M:	Moni Shoua <monis@mellanox.com>
+M:	Zhu Yanjun <yanjunz@mellanox.com>
 L:	linux-rdma@vger.kernel.org
 S:	Supported
-W:	https://github.com/SoftRoCE/rxe-dev/wiki/rxe-dev:-Home
-Q:	http://patchwork.kernel.org/project/linux-rdma/list/
 F:	drivers/infiniband/sw/rxe/
 F:	include/uapi/rdma/rdma_user_rxe.h