x86: baytrail: acpi: Create buffers outside of the methods

Create buffers outside of the methods as ACPICA 20200430 complains
about this:

  Remark 2173 - Creation of named objects within a method is highly
  inefficient, use globals or method local variables instead
  (\_SB.PCI0.LPCB.IURT._CRS)

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>