[ast/syn] Fix buffer labels causing issues applying the SDC file

Signed-off-by: Michael Schaffner <msf@google.com>
diff --git a/hw/top_earlgrey/ip/ast/rtl/aon_osc.sv b/hw/top_earlgrey/ip/ast/rtl/aon_osc.sv
index 86d148d..73f2506 100644
--- a/hw/top_earlgrey/ip/ast/rtl/aon_osc.sv
+++ b/hw/top_earlgrey/ip/ast/rtl/aon_osc.sv
@@ -56,7 +56,7 @@
 
 prim_clock_gating #(
   .NoFpgaGate ( 1'b1 )
-) uu_clk_ckgt (
+) u_clk_ckgt (
   .clk_i ( clk_aon_ext_i ),
   .en_i ( en_osc ),
   .test_en_i ( 1'b0 ),
@@ -83,7 +83,7 @@
 ////////////////////////////////////////
 prim_clock_buf #(
   .NoFpgaBuf ( 1'b1 )
-) uu_buf (
+) u_buf (
   .clk_i ( clk ),
   .clk_o ( aon_clk_o )
 );