Install macsmc battery systemd units with mode 0644 instead of 0755

[SurreptitiousFabric]

The current install-macsmc-battery Makefile target installs these systemd units with mode 0755:

• macsmc-battery-charge-control-end-threshold.path
• macsmc-battery-charge-control-end-threshold.service

install -m0755 -t $(DESTDIR)$(SYSTEMD_UNIT_DIR) macsmc-battery/systemd/macsmc-battery-charge-control-end-threshold.path
install -m0755 -t $(DESTDIR)$(SYSTEMD_UNIT_DIR) macsmc-battery/systemd/macsmc-battery-charge-control-end-threshold.service

As a result, systemd emits the following warnings at every boot:

Configuration file /usr/lib/systemd/system/macsmc-battery-charge-control-end-threshold.path is marked executable. Please remove executable permission bits. Proceeding anyway.
Configuration file /usr/lib/systemd/system/macsmc-battery-charge-control-end-threshold.service is marked executable. Please remove executable permission bits. Proceeding anyway.

Confirmed with asahi-scripts 20260127.1-1 on Arch Linux ARM / Asahi Linux. The path unit is active and charge-threshold persistence functions normally, so this is a packaging-permission issue rather than a functional battery-control failure.

The source-tree entries themselves use mode 100644; only the Makefile installation mode introduces the executable bits.

Suggested fix:

-install -m0755 ... macsmc-battery-charge-control-end-threshold.path
-install -m0755 ... macsmc-battery-charge-control-end-threshold.service
+install -m0644 ... macsmc-battery-charge-control-end-threshold.path
+install -m0644 ... macsmc-battery-charge-control-end-threshold.service

A small installation test asserting 0644 for systemd unit files would prevent recurrence.