samsung-zeroltexx: new device Samsung Galaxy S6 edge (G925F)

This is work to support Samsung Galaxy S6 edge devices (G925F aka zeroltexx). Inspired by some unofficial LineageOS 17.1 port (from https://www.los-legacy.de/17.1/zeroltexx), using the kernel sources from https://github.com/Exynos7420/android_kernel_samsung_exynos7420.

Although there was an earlier report of device support (by Aleksas) on the Wiki page https://wiki.postmarketos.org/wiki/Samsung_Galaxy_S6_Edge_(samsung-zeroltexx) the corresponding port was not available in the repository.

With this port, what works already is:

• Kernel boots
• Display and touch input (tested with Weston and Sxmo)
• USB networking
• Wifi

Firmware files for media (e.g. audio, camera) have not been included, as I wasn't yet able to successfully use these subsystems.

device/testing/device-samsung-zeroltexx/udev/60-persistent-v4l.rules

+# This file is intentionally empty, to disable the default rule with the same name.
+# You can find the default rule in /lib/udev/rules.d/60-persistent-v4l.rules.
+#
+# See https://gitlab.com/postmarketOS/pmaports/-/merge_requests/1160 for why this is needed.