mlxsw: spectrum: Avoid -Wformat-truncation warnings

Give precision identifiers to the two snprintf() formatting the priority
and TC strings to avoid producing these two warnings:

drivers/net/ethernet/mellanox/mlxsw/spectrum.c: In function
'mlxsw_sp_port_get_prio_strings':
drivers/net/ethernet/mellanox/mlxsw/spectrum.c:2132:37: warning: '%d'
directive output may be truncated writing between 1 and 3 bytes into a
region of size between 0 and 31 [-Wformat-truncation=]
   snprintf(*p, ETH_GSTRING_LEN, "%s_%d",
                                     ^~
drivers/net/ethernet/mellanox/mlxsw/spectrum.c:2132:3: note: 'snprintf'
output between 3 and 36 bytes into a destination of size 32
   snprintf(*p, ETH_GSTRING_LEN, "%s_%d",
   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
     mlxsw_sp_port_hw_prio_stats[i].str, prio);
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/net/ethernet/mellanox/mlxsw/spectrum.c: In function
'mlxsw_sp_port_get_tc_strings':
drivers/net/ethernet/mellanox/mlxsw/spectrum.c:2143:37: warning: '%d'
directive output may be truncated writing between 1 and 11 bytes into a
region of size between 0 and 31 [-Wformat-truncation=]
   snprintf(*p, ETH_GSTRING_LEN, "%s_%d",
                                     ^~
drivers/net/ethernet/mellanox/mlxsw/spectrum.c:2143:3: note: 'snprintf'
output between 3 and 44 bytes into a destination of size 32
   snprintf(*p, ETH_GSTRING_LEN, "%s_%d",
   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
     mlxsw_sp_port_hw_tc_stats[i].str, tc);
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlxsw/spectrum.c

@@ -2129,7 +2129,7 @@ static void mlxsw_sp_port_get_prio_strings(u8 **p, int prio)
 	int i;
 
 	for (i = 0; i < MLXSW_SP_PORT_HW_PRIO_STATS_LEN; i++) {
-		snprintf(*p, ETH_GSTRING_LEN, "%s_%d",
+		snprintf(*p, ETH_GSTRING_LEN, "%.29s_%.1d",
 			 mlxsw_sp_port_hw_prio_stats[i].str, prio);
 		*p += ETH_GSTRING_LEN;
 	}
@@ -2140,7 +2140,7 @@ static void mlxsw_sp_port_get_tc_strings(u8 **p, int tc)
 	int i;
 
 	for (i = 0; i < MLXSW_SP_PORT_HW_TC_STATS_LEN; i++) {
-		snprintf(*p, ETH_GSTRING_LEN, "%s_%d",
+		snprintf(*p, ETH_GSTRING_LEN, "%.29s_%.1d",
 			 mlxsw_sp_port_hw_tc_stats[i].str, tc);
 		*p += ETH_GSTRING_LEN;
 	}