arch-arm: Fix GenericTimer param name in BaseArmKvmCPU

Per change [1], the new name for `int_virt` is `int_el1_virt`.

[1] https://gem5-review.googlesource.com/c/public/gem5/+/58109

Change-Id: Idde4ac831c7a323b80272642e6a48b1c5e488135
Signed-off-by: Hoa Nguyen <hoanguyen@ucdavis.edu>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/59309
Maintainer: Bobby Bruce <bbruce@ucdavis.edu>
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Giacomo Travaglini <giacomo.travaglini@arm.com>

src/arch/arm/kvm/base_cpu.cc

@@ -110,7 +110,7 @@ BaseArmKvmCPU::startup()
 
     if (!vm->hasKernelIRQChip())
         virtTimerPin = static_cast<ArmSystem *>(system)\
-            ->getGenericTimer()->params().int_virt->get(tc);
+            ->getGenericTimer()->params().int_el1_virt->get(tc);
 }
 
 Tick