drm/i915/guc: Move lrc desc setup to where it is needed

The LRC descriptor was being initialised early on in the context
registration sequence. It could then be determined that the actual
registration needs to be delayed and the descriptor would be wiped
out. This is inefficient, so move the setup to later in the process
after the point of no return.

v2: Move some split changes into the split patch (and do them
correctly).

Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220302003357.4188363-6-John.C.Harrison@Intel.com

drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c

@@ -2140,6 +2140,8 @@ static int __guc_action_register_context(struct intel_guc *guc,
 					     0, loop);
 }
 
+static void prepare_context_registration_info(struct intel_context *ce);
+
 static int register_context(struct intel_context *ce, bool loop)
 {
 	struct intel_guc *guc = ce_to_guc(ce);
@@ -2150,6 +2152,8 @@ static int register_context(struct intel_context *ce, bool loop)
 	GEM_BUG_ON(intel_context_is_child(ce));
 	trace_intel_context_register(ce);
 
+	prepare_context_registration_info(ce);
+
 	if (intel_context_is_parent(ce))
 		ret = __guc_action_register_multi_lrc(guc, ce, ce->guc_id.id,
 						      offset, loop);
@@ -2304,8 +2308,6 @@ static int try_context_registration(struct intel_context *ce, bool loop)
 	clr_ctx_id_mapping(guc, desc_idx);
 	set_ctx_id_mapping(guc, desc_idx, ce);
 
-	prepare_context_registration_info(ce);
-
 	/*
 	 * The context_lookup xarray is used to determine if the hardware
 	 * context is currently registered. There are two cases in which it