uml: remove code made redundant by CHOOSE_MODE removal

This patch makes a number of simplifications enabled by the removal of
CHOOSE_MODE.  There were lots of functions that looked like

	int foo(args){
		foo_skas(args);
	}

The bodies of foo_skas are now folded into foo, and their declarations (and
sometimes entire header files) are deleted.

In addition, the union uml_pt_regs, which was a union between the tt and skas
register formats, is now a struct, with the tt-mode arm of the union being
removed.

It turns out that usr2_handler was unused, so it is gone.

Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/asm-um/ptrace-x86_64.h b/include/asm-um/ptrace-x86_64.h
index bf61d17..4c47535 100644
--- a/include/asm-um/ptrace-x86_64.h
+++ b/include/asm-um/ptrace-x86_64.h
@@ -76,15 +76,6 @@
         return -ENOSYS;
 }
 
-static inline void arch_switch_to_tt(struct task_struct *from,
-                                     struct task_struct *to)
-{
-}
-
-extern void arch_switch_to_skas(struct task_struct *from,
-				struct task_struct *to);
-
-extern long arch_prctl_skas(struct task_struct *task, int code,
-			    unsigned long __user *addr);
-
+extern long arch_prctl(struct task_struct *task, int code,
+		       unsigned long __user *addr);
 #endif