ACPI: sleep: Fix acpi_pm_pre_suspend() kernel-doc

Fix function name in sleep.c kernel-doc comment
to remove a warning found by running make W=1 LLVM=1.

drivers/acpi/sleep.c:413: warning: expecting prototype for
acpi_pre_suspend(). Prototype was for acpi_pm_pre_suspend() instead.

Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Yang Li <yang.lee@linux.alibaba.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>