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/omap4_panda_defconfig b/configs/omap4_panda_defconfig
index 6b8ce98..a815b9a 100644
--- a/configs/omap4_panda_defconfig
+++ b/configs/omap4_panda_defconfig
@@ -11,6 +11,7 @@
 CONFIG_DEFAULT_FDT_FILE="omap4-panda.dtb"
 CONFIG_SYS_CONSOLE_IS_IN_ENV=y
 CONFIG_SYS_CONSOLE_INFO_QUIET=y
+CONFIG_SPL_MAX_SIZE=0xbc00
 # CONFIG_SPL_FS_EXT4 is not set
 # CONFIG_SPL_I2C is not set
 # CONFIG_SPL_NAND_SUPPORT is not set