AOSCOS: staging: sb105x: revise type of mp_write_room() as unsigned int

Per commit 03b3b1a ("tty: make tty_operations::write_room return
uint"), member function `write_room()' in `struct tty_operations' was
revised from type `int' to type `unsigned int'.

Revise driver code accordingly.

Fixes: "AOSCOS: Revert "staging: sb105x: delete the driver""
Signed-off-by: Mingcong Bai <[email protected]>

Signed-off-by: Kexy Biscuit <[email protected]>

Author: MingcongBai

drivers/staging/sb105x/sb_pci_mp.c

@@ -40,7 +40,7 @@ static int mp_put_char(struct tty_struct *tty, unsigned char ch);
 
 static void mp_put_chars(struct tty_struct *tty);
 static ssize_t mp_write(struct tty_struct *tty, const unsigned char *buf, long unsigned int count);
-static int mp_write_room(struct tty_struct *tty);
+static unsigned int mp_write_room(struct tty_struct *tty);
 static int mp_chars_in_buffer(struct tty_struct *tty);
 static void mp_flush_buffer(struct tty_struct *tty);
 static void mp_send_xchar(struct tty_struct *tty, char ch);
@@ -671,7 +671,7 @@ static ssize_t mp_write(struct tty_struct *tty, const unsigned char *buf, long u
 	return ret;
 }
 
-static int mp_write_room(struct tty_struct *tty)
+static unsigned int mp_write_room(struct tty_struct *tty)
 {
 	struct sb_uart_state *state = tty->driver_data;