am33xx: refactor emif4/ddr to support multiple EMIF instances

The AM33xx emif4/ddr support closely matches what is need to support
TI814x except that TI814x has two EMIF instances. Refactor all the
emif4 helper calls and the config_ddr() init function to use an
additional instance number argument.

Signed-off-by: Matt Porter <mporter@ti.com>
Reviewed-by: Tom Rini <trini@ti.com>
diff --git a/board/ti/am335x/board.c b/board/ti/am335x/board.c
index 758ba15..d61d650 100644
--- a/board/ti/am335x/board.c
+++ b/board/ti/am335x/board.c
@@ -345,13 +345,13 @@
 
 	if (board_is_evm_sk() || board_is_bone_lt())
 		config_ddr(303, MT41J128MJT125_IOCTRL_VALUE, &ddr3_data,
-			   &ddr3_cmd_ctrl_data, &ddr3_emif_reg_data);
+			   &ddr3_cmd_ctrl_data, &ddr3_emif_reg_data, 0);
 	else if (board_is_evm_15_or_later())
 		config_ddr(303, MT41J512M8RH125_IOCTRL_VALUE, &ddr3_evm_data,
-			   &ddr3_evm_cmd_ctrl_data, &ddr3_evm_emif_reg_data);
+			   &ddr3_evm_cmd_ctrl_data, &ddr3_evm_emif_reg_data, 0);
 	else
 		config_ddr(266, MT47H128M16RT25E_IOCTRL_VALUE, &ddr2_data,
-			   &ddr2_cmd_ctrl_data, &ddr2_emif_reg_data);
+			   &ddr2_cmd_ctrl_data, &ddr2_emif_reg_data, 0);
 #endif
 }