net: sctp: update stream->incnt after successful allocation of stream_in

hulk inclusion
category: bugfix
bugzilla: 188766, https://gitee.com/openeuler/kernel/issues/I72J0M


CVE: NA

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The stream->incnt is used to record number of stream_in.
sctp_stream_alloc_in() allocate array of incnt size for sctp_stream_in.
If array is allocated successfully in sctp_stream_init(), stream->incnt
should be updated with variable incnt.

Fixes: 703397c7 ("sctp: leave the err path free in sctp_stream_init to sctp_stream_free")
Signed-off-by: Dong Chenchen <dongchenchen2@huawei.com>
Reviewed-by: Liu Jian <liujian56@huawei.com>
Signed-off-by: Zhang Changzhong <zhangchangzhong@huawei.com>