uml: kernel_thread shouldn't panic

kernel_thread() should just return an error value on do_fork failure, not
panic.

Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/um/kernel/process.c

@@ -97,8 +97,6 @@ int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
 	current->thread.request.u.thread.arg = arg;
 	pid = do_fork(CLONE_VM | CLONE_UNTRACED | flags, 0,
 		      &current->thread.regs, 0, NULL, NULL);
-	if(pid < 0)
-		panic("do_fork failed in kernel_thread, errno = %d", pid);
 	return pid;
 }