ACPICA: Macros: remove pointer math on a null pointer

ACPICA commit 02bbca5070e42d298c9b824300aa0eb8a082d797

Causes warnings on some compilers and/or tools.
Changed ACPI_TO_POINTER to use ACPI_CAST_PTR instead of using
arithmetic.

Link: https://github.com/acpica/acpica/commit/02bbca50
Reported-by: Qian Cai <cai@lca.pw>
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Erik Schmauss <erik.schmauss@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

include/acpi/actypes.h

@@ -506,7 +506,7 @@ typedef u64 acpi_integer;
 
 /* Pointer/Integer type conversions */
 
-#define ACPI_TO_POINTER(i)              ACPI_ADD_PTR (void, (void *) 0, (acpi_size) (i))
+#define ACPI_TO_POINTER(i)              ACPI_CAST_PTR (void, (acpi_size) (i))
 #define ACPI_TO_INTEGER(p)              ACPI_PTR_DIFF (p, (void *) 0)
 #define ACPI_OFFSET(d, f)               ACPI_PTR_DIFF (&(((d *) 0)->f), (void *) 0)
 #define ACPI_PHYSADDR_TO_PTR(i)         ACPI_TO_POINTER(i)