ACPI / tables: Check if id is NULL in acpi_table_parse()

strncmp() does not check if the params are NULL. In acpi_table_parse(),
if @id is NULL, the kernel will panic.

Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com>
Acked-by: Toshi Kani <toshi.kani@hp.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
ACPI / tables: Return proper error codes from acpi_table_parse() and fix comment.

The comment about return value of acpi_table_parse() is incorrect.
This patch fix it.

Since all callers only check if the function succeeded or not, this
patch simplifies the semantics by returning -errno for all failure
cases. This will also simply the comment.

As suggested by Toshi Kani <toshi.kani@hp.com>, also change the stub
in linux/acpi.h to return -ENODEV.

Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Merge branch 'acpi-cleanup-next' into bleeding-edge

* acpi-cleanup-next:
  ACPI / tables: Return proper error codes from acpi_table_parse() and fix comment.
  ACPI / tables: Check if id is NULL in acpi_table_parse()