armv7: LS1021a: enable i-cache in start.S

Delete CONFIG_SKIP_LOWLEVEL_INIT define in ls1021atwr.h and
ls1021aqds.h can let it run cpu_init_cp15 to enable i-cache. First
stage of u-boot can run faster after that. There is a description
about skip lowlevel init in board/freescale/ls1021atwr/README.

Signed-off-by: Xiaoliang Yang <xiaoliang.yang@nxp.com>
Reviewed-by: York Sun <york.sun@nxp.com>
diff --git a/board/freescale/ls1021aqds/README b/board/freescale/ls1021aqds/README
index c561776..6cf7146 100644
--- a/board/freescale/ls1021aqds/README
+++ b/board/freescale/ls1021aqds/README
@@ -110,3 +110,9 @@
 0x00_7E80_0000	0x00_7E80_FFFF	IFC - NAND Flash		64KB
 0x00_7FB0_0000	0x00_7FB0_0FFF	IFC - FPGA			4KB
 0x00_8000_0000	0x00_FFFF_FFFF	DRAM1				2GB
+
+LS1021a rev1.0 Soc specific Options/Settings
+--------------------------------------------
+If the LS1021a Soc is rev1.0, you need modify the configure file.
+Add the following define in include/configs/ls1021aqds.h:
+#define CONFIG_SKIP_LOWLEVEL_INIT
diff --git a/board/freescale/ls1021atwr/README b/board/freescale/ls1021atwr/README
index d2821cb..896a659 100644
--- a/board/freescale/ls1021atwr/README
+++ b/board/freescale/ls1021atwr/README
@@ -107,3 +107,9 @@
 0x00_4000_0000	0x00_5FFF_FFFF	QSPI				512MB
 0x00_6000_0000	0x00_67FF_FFFF	IFC - NOR Flash			128MB
 0x00_8000_0000	0x00_FFFF_FFFF	DRAM1				2GB
+
+LS1021a rev1.0 Soc specific Options/Settings
+--------------------------------------------
+If the LS1021a Soc is rev1.0, you need modify the configure file.
+Add the following define in include/configs/ls1021atwr.h:
+#define CONFIG_SKIP_LOWLEVEL_INIT