hvc_dcc: Simplify put_chars()/get_chars() loops

Casting and anding with 0xff is unnecessary in
hvc_dcc_put_chars() since buf is already a char[].
__dcc_get_char() can't return an int less than 0 since it only
returns a char. Simplify the if statement in hvc_dcc_get_chars()
to take this into account.

Cc: Daniel Walker <[e-mail]>
Signed-off-by: Stephen Boyd <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/tty/hvc/hvc_dcc.c

···
 		while (__dcc_getstatus() & DCC_STATUS_TX)
 			cpu_relax();
 
-		__dcc_putchar((char)(buf[i] & 0xFF));
+		__dcc_putchar(buf[i]);
 	}
 
 	return count;
···
 {
 	int i;
 
-	for (i = 0; i < count; ++i) {
-		int c = -1;
-
+	for (i = 0; i < count; ++i)
 		if (__dcc_getstatus() & DCC_STATUS_RX)
-			c = __dcc_getchar();
-		if (c < 0)
+			buf[i] = __dcc_getchar();
+		else
 			break;
-		buf[i] = c;
-	}
 
 	return i;
 }