arm/ls102xa:add hwconfig setting to support disable unused devices

DEVDISRn registers provides a mechanism for gating clocks of IP blocks
that are not used. Here we implement hwconfig option to allow users
to disable unused peripherals on the board.

For ex. If eSDHC/qDMA/eDMA are unused and with disabled status in dts,
User can enable CONFIG_FSL_DEVICE_DISABLE and set "devdis:esdhc,qdma,edma"
in hwconfig, thus ESDHC controller & eDMA/qDMA will be clock gated to
save more power.

Signed-off-by: Zhuoyu Zhang <Zhuoyu.Zhang@freescale.com>
Reviewed-by: York Sun <yorksun@freescale.com>
diff --git a/board/freescale/ls1021aqds/ls1021aqds.c b/board/freescale/ls1021aqds/ls1021aqds.c
index e585380..655fc64 100644
--- a/board/freescale/ls1021aqds/ls1021aqds.c
+++ b/board/freescale/ls1021aqds/ls1021aqds.c
@@ -12,12 +12,14 @@
 #include <asm/arch/clock.h>
 #include <asm/arch/fsl_serdes.h>
 #include <asm/arch/ls102xa_stream_id.h>
+#include <asm/arch/ls102xa_devdis.h>
 #include <hwconfig.h>
 #include <mmc.h>
 #include <fsl_esdhc.h>
 #include <fsl_ifc.h>
 #include <fsl_sec.h>
 #include <spl.h>
+#include <fsl_devdis.h>
 
 #include "../common/sleep.h"
 #include "../common/qixis.h"
@@ -531,6 +533,9 @@
 	else if (hwconfig("sdhc"))
 		config_board_mux(MUX_TYPE_SDHC);
 
+#ifdef CONFIG_FSL_DEVICE_DISABLE
+	device_disable(devdis_tbl, ARRAY_SIZE(devdis_tbl));
+#endif
 #ifdef CONFIG_FSL_CAAM
 	return sec_init();
 #endif