OvmfPkg/PlatformDxe: fix EFI_HII_HANDLE parameters of internal functions

OvmfPkg/PlatformDxe: fix EFI_HII_HANDLE parameters of internal functions

In the following call tree:

 PlatformInit ()
   mInstalledPackages = HiiAddPackages ()
 GopInstalled ()
    PopulateForm (PackageList = mInstalledPackages)
      CreateResolutionOptions (PackageList)
        HiiSetString (PackageList
      HiiUpdateForm (PackageList)

PlatformDxe passes around an EFI_HII_HANDLE that (a) originates from
HiiAddPackages() and (b) is ultimately passed to HiiSetString() and
HiiUpdateForm(). The intermediate functions PopulateForm() and
CreateResolutionOptions() however take that parameter as an
(EFI_HII_HANDLE*).

There is no bug in practice (because the affected functions never try to
de-reference the "PackageList" parameter, they just pass it on), but the
function prototypes are semantically wrong. Fix that.

This could remain hidden so long because pointer-to-VOID silently converts
to/from any pointer-to-object type, and the UEFI spec mandates that
EFI_HII_HANDLE be a typedef to (VOID*).

Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Philippe Mathieu-Daude <philmd@redhat.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>