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/x530_defconfig b/configs/x530_defconfig
index 47601c4..d145c8f 100644
--- a/configs/x530_defconfig
+++ b/configs/x530_defconfig
@@ -26,6 +26,7 @@
 CONFIG_SILENT_CONSOLE_UPDATE_ON_RELOC=y
 CONFIG_DISPLAY_BOARDINFO_LATE=y
 CONFIG_MISC_INIT_R=y
+CONFIG_SPL_MAX_SIZE=0x22fd0
 CONFIG_SPL_BOARD_INIT=y
 CONFIG_SPL_WATCHDOG=y
 CONFIG_SYS_CBSIZE=256