ACPI: PM: s2idle: Add missing checks to acpi_s2idle_begin_lps0()

Commit 32ece31 ("ACPI: PM: s2idle: Only retrieve constraints
when needed"), that attempted to avoid useless evaluation of LPS0 _DSM
Function 1 in lps0_device_attach(), forgot to add checks for
lps0_device_handle and sleep_no_lps0 to acpi_s2idle_begin_lps0()
where they should be done before calling lpi_device_get_constraints()
or lpi_device_get_constraints_amd().

Add the missing checks.

Fixes: 32ece31 ("ACPI: PM: s2idle: Only retrieve constraints when needed")
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Mario Limonciello (AMD) <superm1@kernel.org>
Link: https://patch.msgid.link/2818730.mvXUDI8C0e@rafael.j.wysocki

Author: rafaeljw

drivers/acpi/x86/s2idle.c

@@ -515,7 +515,8 @@ static struct acpi_scan_handler lps0_handler = {
 
 static int acpi_s2idle_begin_lps0(void)
 {
-	if (pm_debug_messages_on && !lpi_constraints_table) {
+	if (lps0_device_handle && !sleep_no_lps0 && pm_debug_messages_on &&
+	    !lpi_constraints_table) {
 		if (acpi_s2idle_vendor_amd())
 			lpi_device_get_constraints_amd();
 		else