ArmVirtPkg: RMM 1.0-eac5 - Update RSI Version support

The RMM 1.0-eac5 specification updates the RSI version command
to return the highest interface revision which is supported by
the RMM and the lower revision value which indicates:
  a. The RMM supports an interface revision which is compatible
     with the requested revision and the lower revision is equal
     to the requested revision and the status code is RSI_SUCCESS
  b. The RMM does not support the requested version, but the RMM
     supports an interface revision which is lower than the
     requested revision and the status code is RSI_ERROR_INPUT
  c. The RMM does not support an interface revision which is
     compatible with the requested revision and that it supports
     an interface revision that is greater than the requested
     revision. The status code is RSI_ERROR_INPUT and the lower
     revision is equal to the higher revision.

Therefore, update the RsiGetVersion() to return the lower and
higher revision that is supported by the RMM. The RsiGetVersion
function also returns the RSI version that is implemented by
the firmware.

Cc: Ard Biesheuvel <ardb+tianocore@kernel.org>
Cc: Leif Lindholm <quic_llindhol@quicinc.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Sami Mujawar <sami.mujawar@arm.com>