Skip Diagnostic Mode for I2C Resets over FSI In All Cases

This commit restricts running any Diagnostic Mode I2C Resets
over FSI for all cases.  Previously, the mode was only skipped
for FSP-based I2C resets if security was enabled.

Change-Id: Ia2313c01aba4fd4a97b5b1d185786f25a93b4569
CQ:SW430079
Reviewed-on: http://ralgit01.raleigh.ibm.com/gerrit1/59135
Reviewed-by: Dean Sanner <dsanner@us.ibm.com>
Reviewed-by: ILYA SMIRNOV <ismirno@us.ibm.com>
Tested-by: Jenkins Server <pfd-jenkins+hostboot@us.ibm.com>
Disable-CI: Michael Baiocchi <mbaiocch@us.ibm.com>
Tested-by: Jenkins OP Build CI <op-jenkins+hostboot@us.ibm.com>
Tested-by: FSP CI Jenkins <fsp-CI-jenkins+hostboot@us.ibm.com>
Reviewed-by: Nicholas E. Bofferding <bofferdn@us.ibm.com>

src/usr/i2c/i2c.C

@@ -2635,12 +2635,11 @@ errlHndl_t i2cForceResetAndUnlock( TARGETING::Target * i_target,
                 // does not allow diagnostic mode when Secure Boot is enabled.
                 // Note that because I2C is needed before presence detect, we
                 // cannot check the security state of the processor, so we use
-                // the master secure mode as a proxy.  The effectiveness of this
-                // approach assumes nobody enables Secure Boot in hardware but
-                // then loads code with without Secure Boot compiled in, and
-                // that the processors' secure access bits (SABs) all match.
-                else if(   (SECUREBOOT::enabled())
-                        && (i_args.switches.useFsiI2C)) // FSI engine 0
+                // the master secure mode as a proxy.  However, we are unable
+                // to assume that the processors' secure access bits (SABs)
+                // all match early in the IPL.  Therefore we are disabling
+                // diagnostic mode for all FSI-based resets.
+                else if(i_args.switches.useFsiI2C) // FSI engine 0
                 {
                     skipDiagMode = true;
                 }