icache: Fix instruction sent to log

Log the instruction read from the icache, not the instruction (if any)
being written to the icache.

Fixes: 6db626d245 ("icache: Log 36 bits of instruction rather than 32")
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>

icache.vhdl

@@ -625,7 +625,7 @@ begin
 	end if;
         i_out.insn <= insn(31 downto 0);
         i_out.icode <= icode;
-        log_insn <= cache_wr_data(35 downto 0);
+        log_insn <= insn;
 	i_out.valid <= r.hit_valid;
 	i_out.nia <= r.hit_nia;
 	i_out.stop_mark <= r.hit_smark;