linux-postmarketos-exynos5: upgrade to 5.18.5

• upgrade from 5.16.1 to 5.18.5. This upgrade fixes generic camera issue on armv7 (note: a new armv7 camera bug is introduced into 5.19.0 and backported into 5.18.14 (and maybe earlier versions of 5.18.x), i package the version which is known to work, i have not tried 6.0 yet since it needs more rebasing work);
• drop upstreamed patches;
• improve quality of patches making it closer to upstream-ready state;
• add a device-tree binding for usb hub on google-snow which is needed for modem and camera (this gives working camera);
• enable video decoder in kernel and device packages (this is probably not enough for working video decoder, but it will be useful later);
• make boot.img smaller to be further from 8 MiB limit on some android devices.

CC @Grimler