Testcases to verify MMIO and I2C Scoms to Explorer work consistently

Now that MMIO is functional we can enable tests that test writing
with I2C and making sure we read back the same value with MMIO and
vice versa.

Change-Id: I95ac8694117784e6da2a7b38608c9b890d84938e
RTC: 211130
Reviewed-on: http://rchgit01.rchland.ibm.com/gerrit1/79870
Reviewed-by: Christian R. Geddes <crgeddes@us.ibm.com>
Tested-by: Jenkins Server <pfd-jenkins+hostboot@us.ibm.com>
Tested-by: FSP CI Jenkins <fsp-CI-jenkins+hostboot@us.ibm.com>
Tested-by: Jenkins OP Build CI <op-jenkins+hostboot@us.ibm.com>
Tested-by: Jenkins OP HW <op-hw-jenkins+hostboot@us.ibm.com>
Reviewed-by: Matt Derksen <mderkse1@us.ibm.com>
Reviewed-by: Roland Veloz <rveloz@us.ibm.com>
Reviewed-by: Nicholas E. Bofferding <bofferdn@us.ibm.com>

Author: milesg-github