This was done automatically with the following bits of scripting.

The Kconfig choice content was generated with this script snippet:
for i in $(git grep -l CONFIG_ARCH_SUNXI configs/*) ; do
TARGET=$(sed -n -e 's/CONFIG_SYS_EXTRA_OPTIONS="\([^,"]\+\).*/\1/p' $i);
MACH=$(sed -n -e 's/.*CONFIG_\(MACH_SUN.I\)=./\1/p' $i)
echo "config TARGET_$TARGET"
echo " bool \"$TARGET\""
echo " depends on $MACH"
echo
done

defconfigs were updated with a sed script (t):
# Extract board from first entry of CONFIG_SYS_EXTRA_OPTIONS,
/^CONFIG_SYS_EXTRA_OPTIONS/ {
s/^\(CONFIG_SYS_EXTRA_OPTIONS="\)\([^,"]\+\),\?\(.*\)/\1\3\nCONFIG_TARGET_\2=y/;

# Print and delete first line (CONFIG_SYS_EXTRA_OPTIONS), leaving
# CONFIG_TARGET_ in pattern space
P;D;
};

# Move CONFIG_TARGET_ to hold space
/^CONFIG_TARGET/{h;n}

# Print CONFIG_TARGET_ after CONFIG_MACH_ in either SPL or
# normal mode.
/^CONFIG_MACH/{p;g;p;n};
/^\+S:CONFIG_MACH/{p;g;s/^CONFIG_TARGET/+S:&/;p;n};

# Print any remaining lines normally
p;
Run as:
sed -i -n -f t $(git grep -l CONFIG_ARCH_SUNXI configs/*)
and then manually removing the one instance of CONFIG_SYS_EXTRA_OPTIONS="" from
Colombus_defconfig

board/sunxi/Makefile was updated with:
sed -e 's/^\(obj-\$(CONFIG_\)\(.*\)\().*+= dram_.*\)/\1TARGET_\2\3/g' board/sunxi/Makefile
and manually retabbing a few lines to line up again.

The board descriptions could certainly be improved.

Signed-off-by: Ian Campbell
Reviewed-by: Hans de Goede
Signed-off-by: Hans de Goede