configs: update TFABOOT defconfigs for SD boot support

update TFABOOT defconfig for SD boot on below NXP chasis2
and chasis3 platforms:

ls1043a, ls1046a, ls1088a and ls2088a.

Signed-off-by: Rajesh Bhagat <rajesh.bhagat@nxp.com>
Reviewed-by: York Sun <york.sun@nxp.com>
diff --git a/configs/ls1046aqds_tfa_defconfig b/configs/ls1046aqds_tfa_defconfig
index 48d78b4..f77aa23 100644
--- a/configs/ls1046aqds_tfa_defconfig
+++ b/configs/ls1046aqds_tfa_defconfig
@@ -32,6 +32,7 @@
 CONFIG_OF_CONTROL=y
 CONFIG_DEFAULT_DEVICE_TREE="fsl-ls1046a-qds-duart"
 CONFIG_ENV_IS_IN_FLASH=y
+CONFIG_ENV_IS_IN_MMC=y
 CONFIG_ENV_IS_IN_NAND=y
 CONFIG_ENV_IS_IN_SPI_FLASH=y
 CONFIG_DM=y