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/socfpga_secu1_defconfig b/configs/socfpga_secu1_defconfig
index 2fea52b..c55ed87 100644
--- a/configs/socfpga_secu1_defconfig
+++ b/configs/socfpga_secu1_defconfig
@@ -31,6 +31,7 @@
 CONFIG_DISPLAY_BOARDINFO_LATE=y
 CONFIG_CLOCKS=y
 CONFIG_MISC_INIT_R=y
+CONFIG_SPL_PAD_TO=0x10000
 CONFIG_SPL_LEGACY_IMAGE_CRC_CHECK=y
 # CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_USE_SECTOR is not set
 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_PARTITION=0x1