OvmfPkg/EmuVariableFvbRuntimeDxe: eliminate unchecked PcdSetXX() calls
OvmfPkg/EmuVariableFvbRuntimeDxe: eliminate unchecked PcdSetXX() calls

These are deprecated / disabled under the
DISABLE_NEW_DEPRECATED_INTERFACES feature test macro.

Introduce a variable called PcdStatus, and use it to assert the success of
these operations (there is no reason for them to fail here).

Cc: Anthony PERARD <bd4ca9e282b840f7a66451c0c1b8fcfed96ac883@citrix.com>
Cc: Gary Lin <a057d4b27e9e9055b973f54b519db54c22ed5ee8@suse.com>
Cc: Jordan Justen <a79006884ba9cf5f4f7fcbb92a15b208780d8c97@intel.com>
Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=166
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Laszlo Ersek <7437296077edea1cb64451c122c4dac071f0cfbc@redhat.com>
Reviewed-by: Gary Lin <a057d4b27e9e9055b973f54b519db54c22ed5ee8@suse.com>
Tested-by: Gary Lin <a057d4b27e9e9055b973f54b519db54c22ed5ee8@suse.com>
Reviewed-by: Jordan Justen <a79006884ba9cf5f4f7fcbb92a15b208780d8c97@intel.com>

MattDevo/edk2,MattDevo/edk2,MattDevo/edk2,MattDevo/edk2,MattDevo/edk2,MattDevo/edk2,MattDevo/edk2,MattDevo/edk2