drivers/ieee802154_kw41z: Fix interrupt priority

The interrupt priority on KW41Z is from 0..3.  The value of 0x80 is
invalid, so lets set it to 0 for now as all the other interrupt
priorities default to 0 right now.

Signed-off-by: Kumar Gala <kumar.gala@linaro.org>
diff --git a/drivers/ieee802154/ieee802154_kw41z.c b/drivers/ieee802154/ieee802154_kw41z.c
index 57a2506..4c6963b 100644
--- a/drivers/ieee802154/ieee802154_kw41z.c
+++ b/drivers/ieee802154/ieee802154_kw41z.c
@@ -75,7 +75,7 @@
 #define KW41Z_PRE_RX_WAIT_TIME		1
 #define KW40Z_POST_SEQ_WAIT_TIME	1
 
-#define RADIO_0_IRQ_PRIO		0x80
+#define RADIO_0_IRQ_PRIO		0x0
 #define KW41Z_FCS_LENGTH		2
 #define KW41Z_PSDU_LENGTH		125
 #define KW41Z_OUTPUT_POWER_MAX		2