openrisc: Wire up asm-generic/xor.h

crypto/xor.c:25:21: error: asm/xor.h: No such file or directory
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Jonas Bonn <jonas@southpole.se>

arch/openrisc/include/asm/Kbuild

@@ -66,3 +66,4 @@ generic-y += types.h
 generic-y += ucontext.h
 generic-y += user.h
 generic-y += word-at-a-time.h
+generic-y += xor.h