frv: switch to generic fork/vfork/clone

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/arch/frv/include/asm/unistd.h b/arch/frv/include/asm/unistd.h
index 2358634..1807d8e 100644
--- a/arch/frv/include/asm/unistd.h
+++ b/arch/frv/include/asm/unistd.h
@@ -30,6 +30,9 @@
 #define __ARCH_WANT_SYS_RT_SIGACTION
 #define __ARCH_WANT_SYS_RT_SIGSUSPEND
 #define __ARCH_WANT_SYS_EXECVE
+#define __ARCH_WANT_SYS_FORK
+#define __ARCH_WANT_SYS_VFORK
+#define __ARCH_WANT_SYS_CLONE
 
 /*
  * "Conditional" syscalls