arch-arm: Replace 0ing of miscRegs with assignment of reset value

The reset variable in the MiscRegLUTEntry class defines the per-register
reset value. Rather than simply zeroing the misc registers we should
assign them their reset value when clearing them.

As of now the reset variable is unused so using it is functionally
equivalent of calling memset. This will however change once we start
using the reset field

Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Change-Id: If352501738729927c1c9b300e5b0b8c27ce41b79
Reviewed-by: Richard Cooper <richard.cooper@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/70457
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
Maintainer: Jason Lowe-Power <power.jg@gmail.com>

src/arch/arm/isa.cc

@@ -141,7 +141,9 @@ ISA::clear()
     }
 
     SCTLR sctlr_rst = miscRegs[MISCREG_SCTLR_RST];
-    memset(miscRegs, 0, sizeof(miscRegs));
+    for (auto idx = 0; idx < NUM_MISCREGS; idx++) {
+        miscRegs[idx] = lookUpMiscReg[idx].reset();
+    }
 
     initID32(p);