sparc32: support atomic64_t

There is no-one that really require atomic64_t support on sparc32.
But several drivers fails to build without proper atomic64 support.
And for an allyesconfig build for sparc32 this is annoying.

Include the generic atomic64_t support for sparc32.
This has a text footprint cost:

$size vmlinux (before atomic64_t support)
   text    data     bss     dec     hex filename
3578860  134260  108781 3821901  3a514d vmlinux

$size vmlinux (after atomic64_t support)
   text    data     bss     dec     hex filename
3579892  130684  108781 3819357  3a475d vmlinux

text increase (3579892 - 3578860) = 1032 bytes

data decreases - but I fail to explain why!
I have rebuild twice to check my numbers.
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

arch/sparc/Kconfig

@@ -31,6 +31,7 @@ config SPARC
 
 config SPARC32
 	def_bool !64BIT
+	select GENERIC_ATOMIC64
 
 config SPARC64
 	def_bool 64BIT

arch/sparc/include/asm/atomic_32.h

@@ -13,6 +13,8 @@
 
 #include <linux/types.h>
 
+#include <asm-generic/atomic64.h>
+
 #include <asm/system.h>
 
 #define ATOMIC_INIT(i)  { (i) }