arch-arm: Change the type of fault for dc ivac instructions

Change-Id: I00f957a3bc4721a66db62b1257f10e9019a94608
Reviewed-by: Jack Travaglini <giacomo.travaglini@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/7829
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
diff --git a/src/arch/arm/isa/insts/data64.isa b/src/arch/arm/isa/insts/data64.isa
index 7952a95..25bcf78 100644
--- a/src/arch/arm/isa/insts/data64.isa
+++ b/src/arch/arm/isa/insts/data64.isa
@@ -317,8 +317,7 @@
             if (flat_idx == MISCREG_DAIF ||
                 flat_idx == MISCREG_DC_ZVA_Xt ||
                 flat_idx == MISCREG_DC_CVAC_Xt ||
-                flat_idx == MISCREG_DC_CIVAC_Xt ||
-                flat_idx == MISCREG_DC_IVAC_Xt
+                flat_idx == MISCREG_DC_CIVAC_Xt
                 )
                 return std::make_shared<UndefinedInstruction>(
                                     machInst, 0, EC_TRAPPED_MSR_MRS_64,