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/ae350_rv64_spl_defconfig b/configs/ae350_rv64_spl_defconfig
index 8c23eba..856b0c0 100644
--- a/configs/ae350_rv64_spl_defconfig
+++ b/configs/ae350_rv64_spl_defconfig
@@ -16,7 +16,7 @@
 CONFIG_SYS_MONITOR_BASE=0x88000000
 CONFIG_BOOTDELAY=3
 CONFIG_BOARD_EARLY_INIT_F=y
-# CONFIG_BINMAN_FDT is not set
+CONFIG_SPL_MAX_SIZE=0x100000
 CONFIG_SYS_PROMPT="RISC-V # "
 CONFIG_SYS_PBSIZE=1050
 CONFIG_CMD_IMLS=y
@@ -44,3 +44,4 @@
 CONFIG_SYS_NS16550=y
 CONFIG_SPI=y
 CONFIG_ATCSPI200_SPI=y
+# CONFIG_BINMAN_FDT is not set