parisc: Implement kretprobes

Implement kretprobes on parisc, parts stolen from powerpc.

Signed-off-by: Sven Schnelle <svens@stackframe.org>
Signed-off-by: Helge Deller <deller@gmx.de>
diff --git a/arch/parisc/Kconfig b/arch/parisc/Kconfig
index 77126886..c803816 100644
--- a/arch/parisc/Kconfig
+++ b/arch/parisc/Kconfig
@@ -56,6 +56,7 @@
 	select NEED_SG_DMA_LENGTH
 	select HAVE_ARCH_KGDB
 	select HAVE_KPROBES
+	select HAVE_KRETPROBES
 
 	help
 	  The PA-RISC microprocessor is designed by Hewlett-Packard and used