Platform/RPi/AcpiTables: Replace VendorLong () blobs with PinFunction ()

Per https://github.com/MicrosoftDocs/windows-uwp/issues/1751

,
MsftFunctionConfig () calls can be replaced by PinFunction () calls.

Since these had been converted to VendorLong () blobs due to lack of
implementation of MsftFunctionConfig (), we replace them back now
that PinFunction () is available.

Signed-off-by: Pete Batard <pete@akeo.ie>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>