ACPI: video: Use strscpy() instead of strcpy()

Replace strcpy() with strscpy() in the ACPI backlight code.

strcpy() has been deprecated because it is generally unsafe, so help to
eliminate if from the kernel source.

Link: https://github.com/KSPP/linux/issues/88


Signed-off-by: Muhammad Qasim Abdul Majeed <qasim.majeed20@gmail.com>
Link: https://patch.msgid.link/20240703084124.11530-1-qasim.majeed20@gmail.com


[ rjw: Subject and changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>