RDMA/rxe: Prevent faulty rkey generation

RDMA/rxe: Prevent faulty rkey generation

If you create MRs more than 0x10000 times after loading the module,
responder starts to reply NAKs for RDMA/Atomic operations because of rkey
violation detected in check_rkey(). The root cause is that rkeys are
incremented each time a new MR is created and the value overflows into the
range reserved for MWs.

This commit also increases the value of RXE_MAX_MW that has been limited
unlike other parameters.

Fixes: 0994a1bcd5f7 ("RDMA/rxe: Bump up default maximum values used via uverbs")
Link: https://lore.kernel.org/r/20221220080848.253785-2-matsuda-daisuke@fujitsu.com
Signed-off-by: Daisuke Matsuda <matsuda-daisuke@fujitsu.com>
Tested-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>