make atomic_read() behave consistently on xtensa

@@ -15,7 +15,7 @@
 
 #include <linux/stringify.h>
 
-typedef struct { volatile int counter; } atomic_t;
+typedef struct { int counter; } atomic_t;
 
 #ifdef __KERNEL__
 #include <asm/processor.h>

@@ -47,7 +47,7 @@ typedef struct { volatile int counter; }
  *
  * Atomically reads the value of @v.
  */
-#define atomic_read(v)		((v)->counter)
+#define atomic_read(v)		(*(volatile int *)&(v)->counter)
 
 /**
  * atomic_set - set atomic variable