systemc: Remove boost dependency caused by tlm

This commit replaces the tlm header file, which caused the boost
dependency.

Change-Id: Ie4b1af71202522d8139e9a861144863097188072
Signed-off-by: Hoa Nguyen <hoanguyen@ucdavis.edu>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/22624
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Reviewed-by: Bobby R. Bruce <bbruce@ucdavis.edu>
Maintainer: Gabe Black <gabeblack@google.com>
Tested-by: kokoro <noreply+kokoro@google.com>
diff --git a/src/systemc/tlm_bridge/sc_peq.hh b/src/systemc/tlm_bridge/sc_peq.hh
index 386142b..dc0b92b 100644
--- a/src/systemc/tlm_bridge/sc_peq.hh
+++ b/src/systemc/tlm_bridge/sc_peq.hh
@@ -37,8 +37,7 @@
 #ifndef PAYLOAD_EVENT_H_
 #define PAYLOAD_EVENT_H_
 
-// TLM includes
-#include <tlm.h>
+#include "systemc/ext/core/sc_main.hh"
 
 // gem5 includes
 #include <sim/eventq.hh>