net/mlx5e: remove meaningless CFLAGS_tracepoint.o

CFLAGS_tracepoint.o specifies CFLAGS for compiling tracepoint.c but
it does not exist under drivers/net/ethernet/mellanox/mlx5/core/.

CFLAGS_tracepoint.o is unused.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>

drivers/net/ethernet/mellanox/mlx5/core/Makefile

@@ -58,5 +58,3 @@ mlx5_core-$(CONFIG_MLX5_EN_IPSEC) += en_accel/ipsec.o en_accel/ipsec_rxtx.o \
 				     en_accel/ipsec_stats.o
 
 mlx5_core-$(CONFIG_MLX5_EN_TLS) += en_accel/tls.o en_accel/tls_rxtx.o en_accel/tls_stats.o
-
-CFLAGS_tracepoint.o := -I$(src)