amd64, ia32: Remove CopyKeep from function prologue.

These are remnants from back when the prologue was added early and scheduling was not done, yet.
They were there to help the scheduler not to move an IncSP before the copy from sp to bp and thus having two values in sp live at the same time.

ir/be/amd64/bearch_amd64.c

@@ -592,13 +592,9 @@ static void introduce_prologue(ir_graph *const irg)
 		sched_add_after(push, curr_bp);
 		be_set_constr_single_reg_out(curr_bp, 0,
 		                             bp, arch_register_req_type_ignore);
-		curr_sp = be_new_CopyKeep_single(block, curr_sp, curr_bp);
-		sched_add_after(curr_bp, curr_sp);
-		be_set_constr_single_reg_out(curr_sp, 0,
-		                             sp, arch_register_req_type_produces_sp);
 
 		ir_node *incsp = amd64_new_IncSP(block, curr_sp, frame_size, 0);
-		sched_add_after(curr_sp, incsp);
+		sched_add_after(curr_bp, incsp);
 
 		/* make sure the initial IncSP is really used by someone */
 		be_keep_if_unused(incsp);

ir/be/ia32/bearch_ia32.c

@@ -1077,14 +1077,11 @@ static void introduce_prologue(ir_graph *const irg)
 		ir_node *const curr_bp = be_new_Copy(block, curr_sp);
 		sched_add_after(push, curr_bp);
 		be_set_constr_single_reg_out(curr_bp, 0, bp, arch_register_req_type_ignore);
-		curr_sp = be_new_CopyKeep_single(block, curr_sp, curr_bp);
-		sched_add_after(curr_bp, curr_sp);
-		be_set_constr_single_reg_out(curr_sp, 0, sp, arch_register_req_type_produces_sp);
 		edges_reroute_except(initial_bp, curr_bp, push);
 
 		ir_node *incsp = ia32_new_IncSP(block, curr_sp, frame_size, 0);
 		edges_reroute_except(initial_sp, incsp, push);
-		sched_add_after(curr_sp, incsp);
+		sched_add_after(curr_bp, incsp);
 
 		/* make sure the initial IncSP is really used by someone */
 		be_keep_if_unused(incsp);