Convert CONFIG_SPL_PAD_TO et al to Kconfig

This converts the following to Kconfig:
   CONFIG_SPL_PAD_TO
   CONFIG_SPL_MAX_SIZE
   CONFIG_TPL_PAD_TO
   CONFIG_TPL_MAX_SIZE

Note that we need to make TPL_MAX_SIZE be hex, and so move and convert the
existing places.

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/sama5d2_icp_qspiflash_defconfig b/configs/sama5d2_icp_qspiflash_defconfig
index ca5787b..9678b72 100644
--- a/configs/sama5d2_icp_qspiflash_defconfig
+++ b/configs/sama5d2_icp_qspiflash_defconfig
@@ -26,6 +26,7 @@
 CONFIG_BOOTCOMMAND="fatload mmc 0:1 0x21000000 at91-sama5d2_icp.dtb; fatload mmc 0:1 0x22000000 zImage; bootz 0x22000000 - 0x21000000"
 CONFIG_DISPLAY_BOARDINFO_LATE=y
 CONFIG_MISC_INIT_R=y
+CONFIG_SPL_MAX_SIZE=0x10000
 CONFIG_HUSH_PARSER=y
 CONFIG_SYS_CBSIZE=256
 CONFIG_SYS_PBSIZE=276