Input: i8042 - use unsigned char for 0x90

Keep the file consistent and make clear that we mean 144 instead of -112.
Signed-off-by: Christoph Fritz <chf.fritz@googlemail.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

drivers/input/serio/i8042.c

@@ -1063,7 +1063,7 @@ static long i8042_panic_blink(int state)
 #ifdef CONFIG_X86
 static void i8042_dritek_enable(void)
 {
-	char param = 0x90;
+	unsigned char param = 0x90;
 	int error;
 
 	error = i8042_command(&param, 0x1059);