[POWERPC] spufs: Fix compile error

With CONFIG_VIRT_CPU_ACCOUNTING disabled, I got the following error:

linux-2.6/arch/powerpc/platforms/cell/spufs/file.c: In function 'spu_switch_log_notify':
linux-2.6/arch/powerpc/platforms/cell/spufs/file.c:2542: error: implicit declaration of function 'get_tb'
make[4]: *** [arch/powerpc/platforms/cell/spufs/file.o] Error 1

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Paul Mackerras <paulus@samba.org>

arch/powerpc/platforms/cell/spufs/file.c

@@ -32,6 +32,7 @@
 #include <linux/marker.h>
 
 #include <asm/io.h>
+#include <asm/time.h>
 #include <asm/spu.h>
 #include <asm/spu_info.h>
 #include <asm/uaccess.h>