Commit b8d46f01 ("read_only: create folders in build time") creates
unconditionally default folders in spite of we are in a read-only filesystem or
not, however there are different models (dual boot, single boot..) where these
partitions exist or not, so this commit only creates these default partitions
for a read-only filesystem.
https://onedigi.atlassian.net/browse/DEL-8193
Signed-off-by: Arturo Buzarra <arturo.buzarra@digi.com>