Fix regnum predecode of quadrant-2 RVC instructions with 5-bit regnums

(regression caused by adding Zcb)

hdl/hazard3_frontend.v

@@ -576,6 +576,7 @@ always @ (*) begin
 	{1'b0, 1'bz, 16'b0zzzzzzzzzzzzz01}: predecode_rs1_coarse = next_instr[11:7];  // c.addi, c.addi16sp + don't care (jal, li)
 	{1'b0, 1'bz, 16'b100zzzzzzzzzzz10}: predecode_rs1_coarse = next_instr[11:7];  // c.add
 	{1'b0, 1'bz, 16'bz10zzzzzzzzzzz10}: predecode_rs1_coarse = 5'd2;              // c.lwsp, c.swsp
+	{1'b0, 1'bz, 16'bz00zzzzzzzzzzz10}: predecode_rs1_coarse = next_instr[11:7];  // c.slli, c.mv, c.add
 	{1'b0, 1'b1, 16'b1z11zzzzzzzzzz10}: predecode_rs1_coarse = zcmp_pushpop_rs1;  // cm.push, cm.pop*
 	{1'b0, 1'b1, 16'b1z10zzzzz0zzzz10}: predecode_rs1_coarse = zcmp_mvsa01_rs1;   // cm.mvsa01
 	{1'b0, 1'b1, 16'b1z10zzzzz1zzzz10}: predecode_rs1_coarse = zcmp_mva01s_rs1;   // cm.mva01s