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/xilinx_zynqmp_mini_emmc1_defconfig b/configs/xilinx_zynqmp_mini_emmc1_defconfig
index 7b24a2e..0de4e23 100644
--- a/configs/xilinx_zynqmp_mini_emmc1_defconfig
+++ b/configs/xilinx_zynqmp_mini_emmc1_defconfig
@@ -22,6 +22,7 @@
 CONFIG_BOARD_EARLY_INIT_R=y
 # CONFIG_BOARD_LATE_INIT is not set
 CONFIG_CLOCKS=y
+CONFIG_SPL_MAX_SIZE=0x40000
 # CONFIG_CMDLINE_EDITING is not set
 # CONFIG_AUTO_COMPLETE is not set
 CONFIG_SYS_MAXARGS=64