sh_eth: Fix warnings on 64-bit.

Don't cast a plain integer to a pointer.

drivers/net/ethernet/renesas/sh_eth.c: In function ‘sh_eth_chip_reset_giga’:
drivers/net/ethernet/renesas/sh_eth.c:482:22: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
drivers/net/ethernet/renesas/sh_eth.c:483:22: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
drivers/net/ethernet/renesas/sh_eth.c:492:22: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
drivers/net/ethernet/renesas/sh_eth.c:493:22: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]

Signed-off-by: David S. Miller <davem@davemloft.net>