Convert CONFIG_LBA48 et al to Kconfig

This converts the following to Kconfig:
   CONFIG_LBA48
   CONFIG_SYS_64BIT_LBA

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/dh_imx6_defconfig b/configs/dh_imx6_defconfig
index a659e99..7cb4f41 100644
--- a/configs/dh_imx6_defconfig
+++ b/configs/dh_imx6_defconfig
@@ -67,6 +67,7 @@
 CONFIG_ARP_TIMEOUT=200
 CONFIG_BOUNCE_BUFFER=y
 CONFIG_DWC_AHSATA=y
+CONFIG_LBA48=y
 CONFIG_BOOTCOUNT_LIMIT=y
 CONFIG_SYS_DFU_DATA_BUF_SIZE=0x1000000
 CONFIG_DM_I2C=y