libplatsupport,zynq: use proper constant

Signed-off-by: Axel Heider <axelheider@gmx.de>

libplatsupport/src/mach/zynq/serial.c

diff --git a/libplatsupport/src/mach/zynq/serial.c b/libplatsupport/src/mach/zynq/serial.c
index 6b13c30..b0a1de6 100644
--- a/libplatsupport/src/mach/zynq/serial.c
+++ b/libplatsupport/src/mach/zynq/serial.c
@@ -243,7 +243,7 @@
     ps_chardevice_t *d)
 {
     zynq_uart_regs_t *regs = zynq_uart_get_priv(d);
-    regs->isr = UART_IER_RTRIG;
+    regs->isr = UART_ISR_RTRIG;
 }
 
 /*