We now support fetching the PNVM data from a UEFI variable.  Add the
code to read this variable first and use it.  If it's not available,
we fall back to reading the data from the filesystem, as before.
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Link: https://lore.kernel.org/r/iwlwifi.20210211015026.289084803334.Ie234805047df3be84f4235f9dafaf4cdecf0db9a@changeidSigned-off-by: Luca Coelho <luciano.coelho@intel.com>