drivers/ddr/fsl_ddr: Make SR_IE configurable

SR_IE(Self-refresh interrupt enable) is needed for
Hardware Based Self-Refresh. Make it configurable and let
board code handle the rest.

Signed-off-by: Joakim Tjernlund <joakim.tjernlund@transmode.se>
Reviewed-by: York Sun <yorksun@freescale.com>

drivers/ddr/fsl/ctrl_regs.c

@@ -858,7 +858,7 @@ static void set_ddr_sdram_cfg_2(const unsigned int ctrl_num,
 			break;
 		}
 	}
-
+	sr_ie = popts->self_refresh_interrupt_en;
 	num_pr = 1;	/* Make this configurable */
 
 	/*

include/fsl_ddr_sdram.h

@@ -324,6 +324,8 @@ typedef struct memctl_options_s {
 	unsigned int dqs_config;	/* Use DQS? maybe only with DDR2? */
 	/* SREN - self-refresh during sleep */
 	unsigned int self_refresh_in_sleep;
+	/* SR_IE - Self-refresh interrupt enable */
+	unsigned int self_refresh_interrupt_en;
 	unsigned int dynamic_power;	/* DYN_PWR */
 	/* memory data width to use (16-bit, 32-bit, 64-bit) */
 	unsigned int data_bus_width;