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/P1010RDB-PA_NOR_defconfig b/configs/P1010RDB-PA_NOR_defconfig
index 349c647..d1d08fd 100644
--- a/configs/P1010RDB-PA_NOR_defconfig
+++ b/configs/P1010RDB-PA_NOR_defconfig
@@ -19,6 +19,7 @@
 CONFIG_SYS_CONSOLE_IS_IN_ENV=y
 CONFIG_BOARD_EARLY_INIT_F=y
 CONFIG_BOARD_EARLY_INIT_R=y
+CONFIG_SPL_MAX_SIZE=0x18000
 CONFIG_SPL_FLUSH_IMAGE=y
 CONFIG_HUSH_PARSER=y
 CONFIG_SYS_PBSIZE=276