RDMA/ocrdma: Fix permissions for OCRDMA_RESET_STATS

Debugfs file reset_stats is created with S_IRUSR permissions,
but ocrdma_dbgfs_ops_read() doesn't support OCRDMA_RESET_STATS,
whereas ocrdma_dbgfs_ops_write() supports only OCRDMA_RESET_STATS.

The patch fixes misstype with permissions.

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Anton Vasilyev <vasilyev@ispras.ru>
Acked-by: Selvin Xavier <selvin.xavier@broadcom.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>