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/edminiv2_defconfig b/configs/edminiv2_defconfig
index c3293e2..f18e483 100644
--- a/configs/edminiv2_defconfig
+++ b/configs/edminiv2_defconfig
@@ -20,6 +20,7 @@
 # CONFIG_DISPLAY_BOARDINFO is not set
 CONFIG_ARCH_MISC_INIT=y
 CONFIG_RESET_PHY_R=y
+CONFIG_SPL_MAX_SIZE=0xfff0
 CONFIG_SPL_BOARD_INIT=y
 CONFIG_SPL_NOR_SUPPORT=y
 CONFIG_HUSH_PARSER=y