arm64: dts: qcom: Add device tree for Samsung Galaxy S4 Mini Value Edition

arm64: dts: qcom: Add device tree for Samsung Galaxy S4 Mini Value Edition

The Samsung Galaxy S4 Mini Value Edition is an updated version of the
original S4 Mini based on MSM8916. It is similar to the other Samsung
devices based on MSM8916 with only a few minor differences.

The device tree contains initial support for the S4 Mini Value Edition with:
  - UART
  - eMMC/SD card (needs quirk for some reason)
  - Buttons
  - Vibrator
  - WiFi/Bluetooth (WCNSS)
  - USB

Unfortunately, the S4 Mini VE was released with outdated 32-bit only
firmware and never received any update from Samsung. Since the 32-bit
TrustZone firmware is signed there seems to be no way currently to
actually boot this device tree on arm64 Linux at the moment. :(

However, it is possible to use this device tree by compiling an ARM32 kernel
instead. The device tree can be easily built on ARM32 with an #include
and it works really well there. To avoid confusion for others it is still
better to add this device tree on arm64. Otherwise it's easy to forget
to update this one when making some changes that affect all MSM8916 devices.

Maybe someone finds a way to boot ARM64 Linux on this device at some point.
In this case I expect that this device tree can be simply used as-is.

Signed-off-by: Stephan Gerhold <stephan@gerhold.net>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20211004201921.18526-2-stephan@gerhold.net