ACPICA: check null return of ACPI_ALLOCATE_ZEROED() in acpi_db_convert_to_package()

ACPICA commit 4d4547cf13cca820ff7e0f859ba83e1a610b9fd0

ACPI_ALLOCATE_ZEROED() may fail, elements might be NULL and will cause
NULL pointer dereference later.

Link: acpica/acpica@4d4547cf
Signed-off-by: Pei Xiao <xiaopei01@kylinos.cn>
Link: https://patch.msgid.link/tencent_4A21A2865B8B0A0D12CAEBEB84708EDDB505@qq.com
[ rjw: Subject and changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Author: Pei Xiao

drivers/acpi/acpica/dbconvert.c

@@ -174,6 +174,8 @@ acpi_status acpi_db_convert_to_package(char *string, union acpi_object *object)
 	elements =
 	    ACPI_ALLOCATE_ZEROED(DB_DEFAULT_PKG_ELEMENTS *
 				 sizeof(union acpi_object));
+	if (!elements)
+		return (AE_NO_MEMORY);
 
 	this = string;
 	for (i = 0; i < (DB_DEFAULT_PKG_ELEMENTS - 1); i++) {