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/am335x_hs_evm_defconfig b/configs/am335x_hs_evm_defconfig
index 7123a16..36ebff3 100644
--- a/configs/am335x_hs_evm_defconfig
+++ b/configs/am335x_hs_evm_defconfig
@@ -17,6 +17,7 @@
 CONFIG_LOGLEVEL=3
 CONFIG_SYS_CONSOLE_INFO_QUIET=y
 CONFIG_ARCH_MISC_INIT=y
+CONFIG_SPL_MAX_SIZE=0xb0b0
 CONFIG_SPL_FIT_IMAGE_TINY=y
 # CONFIG_SPL_ENV_SUPPORT is not set
 # CONFIG_SPL_FS_EXT4 is not set