avr32: sanitize copy_thread(), switch to generic fork/vfork/clone, kill wrappers

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

arch/avr32/kernel/syscall-stubs.S

@@ -32,24 +32,6 @@ __sys_rt_sigreturn:
 	mov	r12, sp
 	rjmp	sys_rt_sigreturn
 
-	.global	__sys_fork
-	.type	__sys_fork,@function
-__sys_fork:
-	mov	r12, sp
-	rjmp	sys_fork
-
-	.global	__sys_clone
-	.type	__sys_clone,@function
-__sys_clone:
-	mov	r8, sp
-	rjmp	sys_clone
-
-	.global	__sys_vfork
-	.type	__sys_vfork,@function
-__sys_vfork:
-	mov	r12, sp
-	rjmp	sys_vfork
-
 	.global	__sys_mmap2
 	.type	__sys_mmap2,@function
 __sys_mmap2: