ACPICA: Unbreak tools build after switching over to strscpy_pad()

ACPICA: Unbreak tools build after switching over to strscpy_pad()

Commit 97f7d3f9c9ac ("ACPICA: Replace strncpy() with strscpy_pad() in
acpi_ut_safe_strncpy()") switched over the ACPICA code in the kernel to
using strscpy_pad() instead of a combination of strncpy() and manual
NUL-termination of the destination string, but it overlooked the fact
that tools also use the code in question and strscpy_pad() is not
defined in those builds.

Address that by using the original ACPICA code in non-kernel builds.

Fixes: 97f7d3f9c9ac ("ACPICA: Replace strncpy() with strscpy_pad() in acpi_ut_safe_strncpy()")
Reported-by: Jiri Slaby <jirislaby@kernel.org>
Closes: https://lore.kernel.org/all/79e9e913-0fb1-4110-804b-c3b5d0edafe4@kernel
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Kees Cook <kees@kernel.org>
[ rjw: Fixed up the number of added code lines ]
Link: https://patch.msgid.link/12923581.O9o76ZdvQC@rafael.j.wysocki
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>