Dynamic SAR allows changing TX power limits at runtime to comply with
SAR regulations on multiple form factors (e.g. tablet vs. clamshell
mode).  To support this, a new table was added to ACPI, which is
called Extended Wireless Regulatory Descriptor (EWRD).  This table
allows OEMs to define different TX power profiles for each form-factor
or usage mode.

Read this new table and store it in our SAR profiles table, in
preparation for Dynamic SAR support.
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>