fix(draw_buf): init struct member in order

[XuNeo]

Description of the feature or fix

Mentioned in #5709, to fix warning: error: designator order for field 'lv_image_header_t::cf' does not match declaration order in 'lv_image_header_t'

Notes

• Update the Documentation if needed.
• Add Examples if relevant.
• Add Tests if applicable.
• If you added new options to lv_conf_template.h run lv_conf_internal_gen.py and update Kconfig.
• Run scripts/code-format.py (astyle version v3.4.10 needs to be installed) and follow the Code Conventions.
• Mark the Pull request as Draft while you are working on the first version, and mark is as Ready when it's ready for review.
• When changes were requested, re-request review to notify the maintainers.
• Help us to review this Pull Request! Anyone can approve or request changes.

[kisvegabor]

Thanks for the fix!

@XuNeo

Mentioned in #5709,

You can use "fixes #5709" to make GitHub automatically close the linked issue when the PR is merged.
I see now that multiple things are discussed in the issue.