uml: fix inconsistence due to tty_operation change

'put_char' of 'struct tty_operations' has changed from 'void' into 'int'.
This can also shut up compiler warnings.

Cc: Jeff Dike <jdike@addtoit.com>
Signed-off-by: NWANG Cong <wangcong@zeuux.org>
Acked-by: NAlan Cox <alan@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

arch/um/drivers/line.c

@@ -191,9 +191,9 @@ void line_flush_chars(struct tty_struct *tty)
 	line_flush_buffer(tty);
 }
 
-void line_put_char(struct tty_struct *tty, unsigned char ch)
+int line_put_char(struct tty_struct *tty, unsigned char ch)
 {
-	line_write(tty, &ch, sizeof(ch));
+	return line_write(tty, &ch, sizeof(ch));
 }
 
 int line_write(struct tty_struct *tty, const unsigned char *buf, int len)

arch/um/include/line.h

@@ -71,7 +71,7 @@ extern int line_setup(struct line *lines, unsigned int sizeof_lines,
 		      char *init, char **error_out);
 extern int line_write(struct tty_struct *tty, const unsigned char *buf,
 		      int len);
-extern void line_put_char(struct tty_struct *tty, unsigned char ch);
+extern int line_put_char(struct tty_struct *tty, unsigned char ch);
 extern void line_set_termios(struct tty_struct *tty, struct ktermios * old);
 extern int line_chars_in_buffer(struct tty_struct *tty);
 extern void line_flush_buffer(struct tty_struct *tty);