!744 LOS_Panic和魔法键功能中的使用PRINTK打印，依赖任务调度，特殊情况下存在打印不出来的问题

Merge pull request !744 from zhangfanfan2/master

arch/arm/arm/src/los_exc.c

@@ -1237,10 +1237,10 @@ __attribute__((noinline)) VOID LOS_Panic(const CHAR *fmt, ...)
 {
     va_list ap;
     va_start(ap, fmt);
-    UartVprintf(fmt, ap);
+    OsVprintf(fmt, ap, EXC_OUTPUT);
     va_end(ap);
     __asm__ __volatile__("swi 0");
-    while (1);
+    while (1) {}
 }
 
 /* stack protector */

kernel/common/los_magickey.c

@@ -112,7 +112,7 @@ STATIC VOID OsMagicPanic(VOID)
 STATIC VOID OsMagicMemCheck(VOID)
 {
     if (LOS_MemIntegrityCheck(m_aucSysMem1) == LOS_OK) {
-        PRINTK("system memcheck over, all passed!\n");
+        PrintExcInfo("system memcheck over, all passed!\n");
     }
     return;
 }
@@ -130,9 +130,9 @@ INT32 CheckMagicKey(CHAR key, UINT16 consoleId)
     } else if (key == 0x12) { /* ctrl + r */
         magicKeySwitch = ~magicKeySwitch;
         if (magicKeySwitch != 0) {
-            PRINTK("Magic key on\n");
+            PrintExcInfo("Magic key on\n");
         } else {
-            PRINTK("Magic key off\n");
+            PrintExcInfo("Magic key off\n");
         }
         return 1;
     }