This patch fixed the error "bash: mksdimg.sh: No such file
or directory" when building cv18xx_aarch64.
The issue is introduced by commit "bsp: cvitek: removed
useless files after using rttpkgtool".
In addition, in order to unify the logic with riscv as much
as possible, the name of the "milkv-duo256m" directory under
cv18xx_aarch64 is uniformly changed to "duo256m".
This patch also improve the README, adding instructions to
install xz-utils.
Signed-off-by: Chen Wang <unicorn_wang@outlook.com>
Move the combine.sh to under cv18xx_aarch64, so we can
run this script the same as scons and no need to change
cwd.
Rename the folder boot to prebuild just becuase all the
files under boot are prebuild binaries.
Move the prebuilt fip.bin to under prebuild/milkv-duo256m
because it's only for 256.
Update combine.sh accordingly and output fip.bin to the output
folder where we create fip.bin/boot.sd as other bsp.
Signed-off-by: Chen Wang <unicorn_wang@outlook.com>
