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/arch/um/kernel/physmem.c b/arch/um/kernel/physmem.c
index f7b2f35..90e89e8 100644
--- a/arch/um/kernel/physmem.c
+++ b/arch/um/kernel/physmem.c
@@ -10,7 +10,7 @@
 #include "as-layout.h"
 #include "init.h"
 #include "kern.h"
-#include "mode_kern.h"
+#include "mem_user.h"
 #include "os.h"
 
 static int physmem_fd = -1;
@@ -61,7 +61,7 @@
 unsigned long get_kmem_end(void)
 {
 	if (kmem_top == 0)
-		kmem_top = kmem_end_skas;
+		kmem_top = host_task_size - 1024 * 1024;
 	return kmem_top;
 }