remove systemd HDD spindown patch

i haven't used this for several months. it doesn't seem to matter, and
maintaining custom systemd patches is very impractical.

pkgs/overlay.nix

@@ -29,8 +29,6 @@
   jackett = prev.callPackage ./jackett { pkgs = prev; };
   # mozilla keeps nerfing itself and removing configuration options
   firefox-unwrapped = prev.callPackage ./firefox-unwrapped { pkgs = prev; };
-  # fix abrupt HDD poweroffs as during reboot. patching systemd requires rebuilding nearly every package.
-  # systemd = import ./pkgs/systemd { pkgs = prev; };
 
   # patch rpi uboot with something that fixes USB HDD boot
   ubootRaspberryPi4_64bit = prev.callPackage ./ubootRaspberryPi4_64bit { pkgs = prev; };

pkgs/systemd/01-spindown-drive.patch

@@ -1,28 +0,0 @@
-diff --git a/src/shutdown/shutdown.c b/src/shutdown/shutdown.c
-index 2c3cbec02c..8eef305578 100644
---- a/src/shutdown/shutdown.c
-+++ b/src/shutdown/shutdown.c
-@@ -603,6 +603,7 @@ int main(int argc, char *argv[]) {
-                                 execv(args[0], (char * const *) args);
- 
-                                 /* execv failed (kexec binary missing?), so try simply reboot(RB_KEXEC) */
-+                                sleep(15);
-                                 (void) reboot(cmd);
-                                 _exit(EXIT_FAILURE);
-                         }
-@@ -614,6 +615,7 @@ int main(int argc, char *argv[]) {
-                 _fallthrough_;
- 
-         case RB_AUTOBOOT:
-+                sleep(15);
-                 (void) reboot_with_parameter(REBOOT_LOG);
-                 log_info("Rebooting.");
-                 break;
-@@ -630,6 +632,7 @@ int main(int argc, char *argv[]) {
-                 assert_not_reached();
-         }
- 
-+        sleep(15);
-         (void) reboot(cmd);
-         if (errno == EPERM && in_container) {
-                 /* If we are in a container, and we lacked

pkgs/systemd/default.nix

@@ -1,9 +0,0 @@
-{ pkgs }:
-
-(pkgs.systemd.overrideAttrs (upstream: {
-  patches = (upstream.patches or []) ++ [
-    # give the HDD time to spin down before abruptly cutting power
-    ./01-spindown-drive.patch
-  ];
-}))
-