arm64: Make atomic64_t() return "long", not "long long"

arm64 sets CONFIG_64BIT=y and hence uses the "long counter" atomic64_t
definition from include/linux/types.h.  Make atomic64_read() return "long",
not "long long".
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>

arch/arm64/include/asm/atomic.h

@@ -162,7 +162,7 @@ static inline int __atomic_add_unless(atomic_t *v, int a, int u)
  */
 #define ATOMIC64_INIT(i) { (i) }
 
-#define atomic64_read(v)	(*(volatile long long *)&(v)->counter)
+#define atomic64_read(v)	(*(volatile long *)&(v)->counter)
 #define atomic64_set(v,i)	(((v)->counter) = (i))
 
 static inline void atomic64_add(u64 i, atomic64_t *v)