There are two "Src1.Length" with different formats in "send" description
in the PRMs. One is part of ExMsgDesc, is relevant for LSC SFIDs, and
exists if [ExDesc.IsReg]==false. The other is just a 5-bit immediate,
is relevant for other SFIDs too, and exists if ([ExDesc.IsReg]==true)
AND ([ExBSO]==true).
Signed-off-by: Sviatoslav Peleshko <sviatoslav.peleshko@globallogic.com>
Reviewed-by: Sagar Ghuge <sagar.ghuge@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/25657>