use partition.Mountpoint instead of .Device

[klaernie]

use partition.Mountpoint instead of .Device

Under Windows both properties carry the same value, yet under Linux .Device is the name of the block device like /dev/sdc1 and mountpoint is the place in the filesystem where this device is mounted and where one can access the data in it - like /mnt/insta-sdcard.

Hence when trying to access files like MISC/version.txt, DCIM/fileinfo_list.list or MISC/GIS/dji.gis it will not work.

Switching to .Mountpoint means file access under Linux will start to work, and keep working under Windows.

Type:

• [X] Bug fix
• [ ] New feature
• [ ] Breaking change
• [ ] Documentation

Camera:

• [X] GoPro
• [X] Insta360
• [X] DJI
• [ ] Android
• [ ] This PR adds a new camera

Component:

• [ ] Core logic
• [X] Import
• [ ] Merging
• [ ] Firmware Update
• [ ] Video Manipulation

Checklist before approval:

• Linter pass
• Build pass

[KonradIT]

Thanks, I'll apply this PR without passing linter / tests and then fix it myself afterwards.

[klaernie]

Cool! Thanks for merging! Once you've fixed the linter and test I'd happily rebase my other PRs.