Z信号捕获中断优先级改为4，不用0优先级，通过硬件把counter捕获到chan val中了

Signed-off-by: kevin <huhui@sharkgulf.com>

Applications/bsp/bsp.h

@@ -11,7 +11,7 @@
 #define UART_IRQ_PRIORITY      6 
 #define ENC_TIMER_IRQ_PRIORITY 2
 #define ENC_PWM_IRQ_PRIORITY 2
-#define ENC_I_EXIT_IRQ_PRIORITY 0
+#define ENC_I_EXIT_IRQ_PRIORITY 4
 #define ENC_OTHER_IRQ_PRIORITY 8
 
 #define THREE_SHUNTS_SAMPLE 1