intel: Fix addressing of shader scratch surfaces for Xe2+ platforms.

Most remaining changes required to support scratch space on Xe2 are related to the removal of the legacy extended descriptor surface state format for the UGM shared function (other shared functions still support it), which means that the ExBSO mode is always enabled now for UGM messages. The downside of having the whole 32 bits of an address register available for addressing surface state objects is that an additional shift instruction is required in some cases in order to setup the extended descriptor, and some fields that were formerly part of the extended descriptor like the extended message length are now baked into the instruction.