IMAGE_CMD_xxx commands are always inlined within do_image_xxx.
When IMAGE_CMD_xxx is defined as a function (e.g. IMAGE_CMD_btrfs,
IMAGE_CMD_cpio, etc), a redundant copy of the function will be emitted
by default. Remove IMAGE_CMD_xxx 'func' flags to prevent that.
Signed-off-by: Andre McCurdy <armccurdy@gmail.com> Signed-off-by: Ross Burton <ross.burton@intel.com>