Fix this error:

  CC      drivers/net/ethernet/stmicro/stmmac/mmc_core.o
drivers/net/ethernet/stmicro/stmmac/mmc_core.c: In function 'dwmac_mmc_ctrl':
drivers/net/ethernet/stmicro/stmmac/mmc_core.c:143:2: error: implicit
  declaration of function 'pr_debug' [-Werror=implicit-function-declaration]

Signed-off-by: Stefan Roese <sr <at> denx.de>
Cc: Giuseppe Cavallaro <peppe.cavallaro <at> st.com>
---
 drivers/net/ethernet/stmicro/stmmac/mmc_core.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/mmc_core.c b/drivers/net/ethernet/stmicro/stmmac/mmc_core.c
index 41e6b33..c07cfe9 100644
--- a/drivers/net/ethernet/stmicro/stmmac/mmc_core.c
+++ b/drivers/net/ethernet/stmicro/stmmac/mmc_core.c
@@ -22,6 +22,7 @@
   Author: Giuseppe Cavallaro <peppe.cavallaro <at> st.com>
 *******************************************************************************/

+#include <linux/kernel.h>
 #include <linux/io.h>
 #include "mmc.h"

--