net: hns: fix uninitialized data use

When dev_dbg() is enabled, we print uninitialized data, as gcc-7.0.1
now points out:

ethernet/hisilicon/hns/hns_dsaf_main.c: In function 'hns_dsaf_set_promisc_tcam':
ethernet/hisilicon/hns/hns_dsaf_main.c:2947:75: error: 'tbl_tcam_data.low.val' may be used uninitialized in this function [-Werror=maybe-uninitialized]
ethernet/hisilicon/hns/hns_dsaf_main.c:2947:75: error: 'tbl_tcam_data.high.val' may be used uninitialized in this function [-Werror=maybe-uninitialized]

We also pass the data into hns_dsaf_tcam_mc_cfg(), which might later
use it (not sure about that), so it seems safer to just always initialize
the tbl_tcam_data structure.

Fixes: 1f5fa2dd ("net: hns: fix for promisc mode in HNS driver")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: David S. Miller <davem@davemloft.net>