Merge branch 'acpica'
* acpica:
ACPICA: Update version to 20130725.
ACPICA: Update names for walk_namespace callbacks to clarify usage.
ACPICA: Return error if DerefOf resolves to a null package element.
ACPICA: Make ACPI Power Management Timer (PM Timer) optional.
ACPICA: Fix divergences of the commit - ACPICA: Expose OSI version.
ACPICA: Fix possible fault for methods that optionally have no return value.
ACPICA: DeRefOf operator: Update to fully resolve FieldUnit and BufferField refs.
ACPICA: Emit all unresolved method externals in a text block
ACPICA: Export acpi_tb_validate_rsdp().
ACPI: Add facility to remove all _OSI strings
ACPI: Add facility to disable all _OSI OS vendor strings
ACPICA: Add acpi_update_interfaces() public interface
ACPICA: Update version to 20130626
ACPICA: Fix compiler warnings for casting issues (only some compilers)
ACPICA: Remove restriction of 256 maximum GPEs in any GPE block
ACPICA: Disassembler: Expand maximum output string length to 64K
ACPICA: TableManager: Export acpi_tb_scan_memory_for_rsdp()
ACPICA: Update comments about behavior when _STA does not exist