[PARISC] Redefine ATOMIC_INIT and ATOMIC64_INIT to drop the casts

The following build error occured during a parisc build with
swap-over-NFS patches applied.

net/core/sock.c:274:36: error: initializer element is not constant
net/core/sock.c:274:36: error: (near initialization for 'memalloc_socks')
net/core/sock.c:274:36: error: initializer element is not constant

Dave Anglin says:
> Here is the line in sock.i:
>
> struct static_key memalloc_socks = ((struct static_key) { .enabled =
> ((atomic_t) { (0) }) });

The above line contains two compound literals.  It also uses a designated
initializer to initialize the field enabled.  A compound literal is not a
constant expression.

The location of the above statement isn't fully clear, but if a compound
literal occurs outside the body of a function, the initializer list must
consist of constant expressions.

Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Mel Gorman <mgorman@suse.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

arch/parisc/include/asm/atomic.h

@@ -141,7 +141,7 @@ static __inline__ int __atomic_add_unless(atomic_t *v, int a, int u)
 
 #define atomic_sub_and_test(i,v)	(atomic_sub_return((i),(v)) == 0)
 
-#define ATOMIC_INIT(i)	((atomic_t) { (i) })
+#define ATOMIC_INIT(i)	{ (i) }
 
 #define smp_mb__before_atomic_dec()	smp_mb()
 #define smp_mb__after_atomic_dec()	smp_mb()
@@ -150,7 +150,7 @@ static __inline__ int __atomic_add_unless(atomic_t *v, int a, int u)
 
 #ifdef CONFIG_64BIT
 
-#define ATOMIC64_INIT(i) ((atomic64_t) { (i) })
+#define ATOMIC64_INIT(i) { (i) }
 
 static __inline__ s64
 __atomic64_add_return(s64 i, atomic64_t *v)