[ot] hw/opentitan: ot_flash: Re-enable flash memory region on reset

Although the `DIS` disablement register was being reset on reset, the
flash mmio `mem` memory region's enablement was not being reset. This
caused some difficult to debug issues due to QEMU's non-determinism
where resets could occur before or after SW disables the flash,
essentially permanently locking Earlgrey out of its flash.

Signed-off-by: Alex Jones <[email protected]>

Author: AlexJones0

hw/opentitan/ot_flash.c

@@ -3268,6 +3268,9 @@ static void ot_flash_reset_enter(Object *obj, ResetType type)
 
     s->csrs[R_CSR0_REGWEN] = 0x1u;
 
+    /* restore flash memory region enablement if previously disabled */
+    memory_region_set_enabled(&s->mmio.mem, true);
+
     s->latched_alerts = 0u;
 
     s->lc_broadcast.incoming_signal_bm = 0u;