PTRACE_POKEDATA consolidation

Identical implementations of PTRACE_POKEDATA go into generic_ptrace_pokedata()
function.

AFAICS, fix bug on xtensa where successful PTRACE_POKEDATA will nevertheless
return EPERM.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/arch/powerpc/kernel/ptrace.c b/arch/powerpc/kernel/ptrace.c
index 581d427..8a177bd 100644
--- a/arch/powerpc/kernel/ptrace.c
+++ b/arch/powerpc/kernel/ptrace.c
@@ -413,11 +413,7 @@
 	/* If I and D space are separate, this will have to be fixed. */
 	case PTRACE_POKETEXT: /* write the word at location addr. */
 	case PTRACE_POKEDATA:
-		ret = 0;
-		if (access_process_vm(child, addr, &data, sizeof(data), 1)
-				== sizeof(data))
-			break;
-		ret = -EIO;
+		ret = generic_ptrace_pokedata(child, addr, data);
 		break;
 
 	/* write the word at location addr in the USER area */