drm/amdgpu/mes12: optimize MES pipe FW version fetching

commit 34779e14 upstream.

Don't fetch it again if we already have it.  It seems the
registers don't reliably have the value at resume in some
cases.

Fixes: 785f0f9f ("drm/amdgpu: Add mes v12_0 ip block support (v4)")
Reviewed-by: Shaoyun.liu <Shaoyun.liu@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit 9e7b08d2)
Cc: stable@vger.kernel.org # 6.12.x
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>