thermosphere: use barriers and caches *properly*. Cache code refactoring

- set/way cache ops create losses of coherency, do not broadcast and are only meant to be used on boot, period.

Cache ops by VA are **the only way** to do data cache maintenance.

Fix a bug where the L2 cache was evicted by each core. It shouldn't have.

- Cleaning dcache to PoU and invalidating icache to PoU, by VA is sufficient for self-modifying code

- Since we operate within a single cluster and don't do DMA, we almost always operate within the inner shareability domain

(commit untested on real hw)

thermosphere/src/breakpoints.c

@@ -19,7 +19,6 @@
 #include "breakpoints_watchpoints_load.h"
 #include "utils.h"
 #include "sysreg.h"
-#include "arm.h"
 
 BreakpointManager g_breakpointManager = {0};
 
@@ -49,7 +48,7 @@ static void commitAndBroadcastBreakpointHandler(void *p)
 
 static inline void commitAndBroadcastBreakpoints(void)
 {
-    __dmb_sy();
+    __dmb();
     executeFunctionOnAllCores(commitAndBroadcastBreakpointHandler, NULL, true);
 }