PC stucks at 1004c WFI

**Type of issue**: PC stucks at 1004c WFI and nerver go to 0x800000

**Impact**:

**Development Phase**: request | proposal

**Other information**

**If the current behavior is a bug, please provide the steps to reproduce the problem:**
1. Download https://github.com/chipsalliance/rocket-chip/tree/7cd3352c3b802c3c50cb864aee828c6106414bb3
2. make CONFIG=...
3. ./emulator...
**What is the current behavior?**
Stuck at 1004c
**What is the expected behavior?**
Pass
**Please tell us about your environment:**
Ubuntu 18.04
**What is the use case for changing the behavior?**
None

Check out commit 7cd3352c3b802c3c50cb864aee828c6106414bb3 and reproduce the issue using the stated make CONFIG=... and ./emulator... commands on Ubuntu 18.04. Record the configuration and execution around PC 0x1004c and WFI, then compare it with the expected transition to 0x800000. Done means the emulator passes instead of remaining at 0x1004c.

Written by the indexing model from the issue text.