UML: make several more things static

- Make some variables and functions static, since they don't need to be
  global.

- Remove an unused function - arch/um/kernel/time.c::sched_clock().

- Clean the style a bit as complained by checkpatch.pl.

Cc: Jeff Dike <jdike@addtoit.com>
Signed-off-by: WANG Cong <wangcong@zeuux.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/um/os-Linux/sigio.c

@@ -530,7 +530,7 @@ static void tty_close(int master, int slave)
 		printk(UM_KERN_CONT "No, enabling workaround\n");
 }
 
-void __init check_sigio(void)
+static void __init check_sigio(void)
 {
 	if ((access("/dev/ptmx", R_OK) < 0) &&
 	    (access("/dev/ptyp0", R_OK) < 0)) {