Revert "Drop the ryzenadj service, now built in."

This reverts commit 7d3ae0fff7.

README.md

@@ -123,6 +123,7 @@ Variant designed for usage as an alternative to SteamOS on the Steam Deck, and f
 - Applies SteamOS's kernel parameters.
 - Color calibrated display profiles for matte and reflective Steam Deck screens included.
 - Default-disabled power-user features, including:
+    - Service for low-risk undervolting of the Steam Deck via [RyzenAdj](https://github.com/FlyGoat/RyzenAdj) and [Ryzen SMU](https://gitlab.com/leogx9r/ryzen_smu), see `ryzenadj.service` and `/etc/default/ryzenadj`.
     - Service for limiting the max charge level of the battery, see `batterylimit.service` and `/etc/default/batterylimit`. <sup><sub>(Works even when the device is off)</sub></sup>
     - Built in support for display overclocking. For example, add `GAMESCOPE_OVERRIDE_REFRESH_RATE=40,70` to `/etc/environment`.
     - 32GB RAM mod your Steam Deck? Enjoy double the maximum VRAM amount, automatically applied. <sup><sub>(Can you share your soldering skills?)</sub></sup>

system_files/deck/shared/usr/etc/default/ryzenadj

@@ -0,0 +1,8 @@
+# https://github.com/NGnius/PowerTools/issues/84#issuecomment-1482736698
+# https://www.amd.com/system/files/documents/faq-curve-optimizer.pdf
+# Expect your UV to be 3-5x your set curve value. IE: -5 = -15mv to -25mv
+# 0x100000 - 5 (Range: -30, 30)
+UNDERVOLT_AMOUNT=0xFFFFB
+# WARNING: As with any undervolt exercise caution.
+# There is no guarantee you won't damage your hardware.
+# USE AT YOUR OWN RISK.

system_files/deck/shared/usr/lib/systemd/system/ryzenadj.service

@@ -0,0 +1,11 @@
+[Unit]
+Description=CPU Curve Undervolt for Steam Deck
+
+[Service]
+Type=oneshot
+EnvironmentFile=-/etc/default/%p
+ExecStartPre=/usr/bin/sleep 10
+ExecStart=/usr/bin/ryzenadj --set-coall=${UNDERVOLT_AMOUNT}
+
+[Install]
+WantedBy=multi-user.target suspend.target hibernate.target hybrid-sleep.target suspend-then-hibernate.target ac.target battery.target