uml: throw out CHOOSE_MODE

The next stage after removing code which depends on CONFIG_MODE_TT is removing
the CHOOSE_MODE abstraction, which provided both compile-time and run-time
branching to either tt-mode or skas-mode code.

This patch removes choose-mode.h and all inclusions of it, and replaces all
CHOOSE_MODE invocations with the skas branch.  This leaves a number of trivial
functions which will be dealt with in a later patch.

There are some changes in the uaccess and tls support which go somewhat beyond
this and eliminate some of the now-redundant functions.

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/drivers/chan_user.c b/arch/um/drivers/chan_user.c
index d29e56d..74f22d2 100644
--- a/arch/um/drivers/chan_user.c
+++ b/arch/um/drivers/chan_user.c
@@ -264,8 +264,7 @@
 		return;
 
 	pid = tcgetpgrp(fd);
-	if (!CHOOSE_MODE_PROC(is_tracer_winch, is_skas_winch, pid, fd, tty) &&
-	    (pid == -1)) {
+	if (!is_skas_winch(pid, fd, tty) && (pid == -1)) {
 		thread = winch_tramp(fd, tty, &thread_fd, &stack);
 		if (thread < 0)
 			return;