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/k2g_evm_defconfig b/configs/k2g_evm_defconfig
index fc33225..e98e953 100644
--- a/configs/k2g_evm_defconfig
+++ b/configs/k2g_evm_defconfig
@@ -26,6 +26,7 @@
 CONFIG_BOOTCOMMAND="run findfdt; run envboot; run init_${boot}; run get_mon_${boot} run_mon; run set_name_pmmc get_pmmc_${boot} run_pmmc; run get_kern_${boot}; run init_fw_rd_${boot}; run get_fdt_${boot}; run run_kern"
 CONFIG_SYS_CONSOLE_INFO_QUIET=y
 CONFIG_BOARD_EARLY_INIT_F=y
+CONFIG_SPL_MAX_SIZE=0xfff8
 CONFIG_SPL_I2C=y
 CONFIG_SPL_NAND_DRIVERS=y
 CONFIG_SPL_NAND_ECC=y