asm-generic/sembuf: Update architecture related information in comment

The structure came originally from x86_32 but is used by most of the
architectures now. Update the comment which says it is for x86 only.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/64efe033394b6f0dfef043a63fd8897a81ba6d16.1589970173.git.viresh.kumar@linaro.org'

include/uapi/asm-generic/sembuf.h

@@ -6,9 +6,9 @@
 #include <asm/ipcbuf.h>
 
 /*
- * The semid64_ds structure for x86 architecture.
- * Note extra padding because this structure is passed back and forth
- * between kernel and user space.
+ * The semid64_ds structure for most architectures (though it came from x86_32
+ * originally). Note extra padding because this structure is passed back and
+ * forth between kernel and user space.
  *
  * semid64_ds was originally meant to be architecture specific, but
  * everyone just ended up making identical copies without specific