configs: Enable SPL_FSL_PBL for some LayerScape platforms

In commit <db4080d56dec>, SPL_FSL_PBL is removed from the configs of
some LayerScape platforms. Actually, SPL_FSL_PBL is needed for SD/NAND
boot on LS1021A/LS1043A/LS1046A to create boot binary having SPL binary
in PBI format concatenated with u-boot binary. SPL_FRAMEWORK is used on
these platforms too.

Signed-off-by: Alison Wang <alison.wang@nxp.com>
Reviewed-by: Priyanka Jain <priyanka.jain@nxp.com>
diff --git a/configs/ls1021aqds_nand_defconfig b/configs/ls1021aqds_nand_defconfig
index b6c0f39..8cac448 100644
--- a/configs/ls1021aqds_nand_defconfig
+++ b/configs/ls1021aqds_nand_defconfig
@@ -10,6 +10,7 @@
 CONFIG_NR_DRAM_BANKS=1
 CONFIG_SPL=y
 CONFIG_AHCI=y
+CONFIG_SPL_FSL_PBL=y
 CONFIG_SPL_TEXT_BASE=0x10000000
 CONFIG_FIT=y
 CONFIG_FIT_VERBOSE=y