arm, davinci: Use CONFIG_SPL_PAD_TO for padding the SPL in an ais image

The commits

commit b7b5f1a16c
Author: Albert ARIBAUD <albert.u.boot@aribaud.net>
da850evm, da850_am18xxevm: convert to CONFIG_SPL_MAX_FOOTPRINT

and

commit e7497891e3
Author: Albert ARIBAUD <albert.u.boot@aribaud.net>
cam_enc_4xx: convert to CONFIG_SPL_MAX_FOOTPRINT

replaced CONFIG_SPL_MAX_SIZE by CONFIG_SPL_MAX_FOOTPRINT. However,
CONFIG_SPL_MAX_SIZE is used in the Makefile for padding the SPL
when preparing an u-boot.ais image. By removing CONFIG_SPL_MAX_SIZE
said commits broke the ais image of the da850evm and cam_enc_4xx
configurations.

This patch converts the u-boot.ais target to use CONFIG_SPL_PAD_TO
instead of CONFIG_SPL_MAX_SIZE for padding the SPL and adds
a #define CONFIG_SPL_PAD_TO where it is required.

Signed-off-by: Christian Riesch <christian.riesch@omicron.at>
Reported-by: Tom Taylor <ttaylor.tampa@gmail.com>
Cc: Sudhakar Rajashekhara <sudhakar.raj@ti.com>
Cc: Heiko Schocher <hs@denx.de>
Cc: Albert ARIBAUD <albert.u.boot@aribaud.net>

Makefile

@@ -890,7 +890,7 @@ MKIMAGEFLAGS_u-boot-spl.ais = -s -n $(if $(CONFIG_AIS_CONFIG_FILE), \
 spl/u-boot-spl.ais: spl/u-boot-spl.bin FORCE
 	$(call if_changed,mkimage)
 
-OBJCOPYFLAGS_u-boot.ais = -I binary -O binary --pad-to=$(CONFIG_SPL_MAX_SIZE)
+OBJCOPYFLAGS_u-boot.ais = -I binary -O binary --pad-to=$(CONFIG_SPL_PAD_TO)
 u-boot.ais: spl/u-boot-spl.ais u-boot.img FORCE
 	$(call if_changed,pad_cat)
 

include/configs/da850evm.h

@@ -386,6 +386,7 @@
 #define CONFIG_SPL_STACK	0x8001ff00
 #define CONFIG_SPL_TEXT_BASE	0x80000000
 #define CONFIG_SPL_MAX_FOOTPRINT	32768
+#define CONFIG_SPL_PAD_TO	32768
 #endif
 
 /* Load U-Boot Image From MMC */