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/controlcenterdc_defconfig b/configs/controlcenterdc_defconfig
index 18b854e..e7650f5 100644
--- a/configs/controlcenterdc_defconfig
+++ b/configs/controlcenterdc_defconfig
@@ -32,6 +32,7 @@
 CONFIG_DISPLAY_BOARDINFO_LATE=y
 CONFIG_BOARD_LATE_INIT=y
 CONFIG_LAST_STAGE_INIT=y
+CONFIG_SPL_MAX_SIZE=0x27fd0
 CONFIG_SPL_BOARD_INIT=y
 CONFIG_SPL_SYS_MALLOC_SIMPLE=y
 CONFIG_SPL_I2C=y