ACPICA: Use os_allocate_zeroed

ACPICA commit 2b896c59e53243c95600f2a3f7e1fd02c044cb37

Eliminates an unnecessary memset.

Suggested-by: Amitoj Kaur Chawla <amitoj1606@gmail.com>
Link: https://github.com/acpica/acpica/commit/2b896c59


Signed-off-by: Amitoj Kaur Chawla <amitoj1606@gmail.com>
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>