tty: serial: men_z135_uart: Don't activate TX Space available IRQ on startup

Don't activate the TX Space available IRQ on startup, or a simple
$ cat /dev/ttyHSU0
will cause an endless amount of IRQs, as there is always space in
the TX FIFO available if no data is going to be sent.

Also correct comments for IRQ names (RX and TX swapped).
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@men.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/men_z135_uart.c

@@ -41,8 +41,8 @@
 #define IS_IRQ(x) ((x) & 1)
 #define IRQ_ID(x) (((x) >> 1) & 7)
 
-#define MEN_Z135_IER_RXCIEN BIT(0)		/* TX Space IRQ */
-#define MEN_Z135_IER_TXCIEN BIT(1)		/* RX Space IRQ */
+#define MEN_Z135_IER_RXCIEN BIT(0)		/* RX Space IRQ */
+#define MEN_Z135_IER_TXCIEN BIT(1)		/* TX Space IRQ */
 #define MEN_Z135_IER_RLSIEN BIT(2)		/* Receiver Line Status IRQ */
 #define MEN_Z135_IER_MSIEN  BIT(3)		/* Modem Status IRQ */
 #define MEN_Z135_ALL_IRQS (MEN_Z135_IER_RXCIEN		\
@@ -576,7 +576,8 @@ static int men_z135_startup(struct uart_port *port)
 
 	conf_reg = ioread32(port->membase + MEN_Z135_CONF_REG);
 
-	conf_reg |= MEN_Z135_ALL_IRQS;
+	/* Activate all but TX space available IRQ */
+	conf_reg |= MEN_Z135_ALL_IRQS & ~MEN_Z135_IER_TXCIEN;
 	conf_reg &= ~(0xff << 16);
 	conf_reg |= (txlvl << 16);
 	conf_reg |= (rxlvl << 20);