systemc: set Gem5ToTlmBridge blockingRrequest with TLM_UPDATE returning

systemc: set Gem5ToTlmBridge blockingRrequest with TLM_UPDATE returning

In Gem5ToTlmBridge::pec, the function expects blockingRequest should be
set no matter the tlm peer returns TLM_UPDATE or TLM_ACCEPTED.
However, current implementation only sets blockingRequest when the tlm
peer returns TLM_ACCEPTED. We should also set blockingRequest when the
tlm peer returns TLM_UPDATE.

Change-Id: I87bba3201cd68d52ded93c9c200f4fa4a40bdf5b
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/39815
Reviewed-by: Earl Ou <shunhsingou@google.com>
Maintainer: Gabe Black <gabe.black@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>