net/mlx5: Add MPCNT register infrastructure

Add the needed infrastructure for future use of MPCNT register.

Signed-off-by: Gal Pressman <galp@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
diff --git a/include/linux/mlx5/driver.h b/include/linux/mlx5/driver.h
index 69c4661..f4d6d39 100644
--- a/include/linux/mlx5/driver.h
+++ b/include/linux/mlx5/driver.h
@@ -126,6 +126,7 @@ enum {
 	MLX5_REG_HOST_ENDIANNESS = 0x7004,
 	MLX5_REG_MCIA		 = 0x9014,
 	MLX5_REG_MLCR		 = 0x902b,
+	MLX5_REG_MPCNT		 = 0x9051,
 	MLX5_REG_MTPPS		 = 0x9053,
 	MLX5_REG_MTPPSE		 = 0x9054,
 	MLX5_REG_MCAM		 = 0x907f,