[style] fix warnings -Wextra-semi (#5566)

src/core/mac/mac_frame.hpp

@@ -557,7 +557,7 @@ public:
      * @retval TRUE if the Source Address is present, FALSE otherwise.
      *
      */
-    bool IsSrcPanIdPresent(void) const { return IsSrcPanIdPresent(GetFrameControlField()); };
+    bool IsSrcPanIdPresent(void) const { return IsSrcPanIdPresent(GetFrameControlField()); }
 
     /**
      * This method gets the Source PAN Identifier.

src/core/mac/sub_mac.hpp

@@ -489,7 +489,7 @@ public:
      * @returns The current MAC frame counter value.
      *
      */
-    uint32_t GetFrameCounter(void) const { return mFrameCounter; };
+    uint32_t GetFrameCounter(void) const { return mFrameCounter; }
 
     /**
      * This method sets the current MAC Frame Counter value.

src/core/meshcop/meshcop.hpp

@@ -434,7 +434,7 @@ private:
     uint8_t GetNumBits(void) const { return (mLength * CHAR_BIT); }
 
     uint8_t BitIndex(uint8_t aBit) const { return (mLength - 1 - (aBit / CHAR_BIT)); }
-    uint8_t BitFlag(uint8_t aBit) const { return static_cast<uint8_t>(1U << (aBit % CHAR_BIT)); };
+    uint8_t BitFlag(uint8_t aBit) const { return static_cast<uint8_t>(1U << (aBit % CHAR_BIT)); }
 
     bool GetBit(uint8_t aBit) const { return (m8[BitIndex(aBit)] & BitFlag(aBit)) != 0; }
     void SetBit(uint8_t aBit) { m8[BitIndex(aBit)] |= BitFlag(aBit); }

src/core/net/dns_headers.hpp

@@ -507,7 +507,7 @@ public:
     {
         SetType(aType);
         SetClass(aClass);
-    };
+    }
 
     /**
      * This method returns the type of the question.

src/core/utils/flash.hpp

@@ -159,7 +159,7 @@ private:
 
             mLength   = 0;
             mReserved = 0xffff;
-        };
+        }
 
         uint16_t GetKey(void) const { return mKey; }
         void     SetKey(uint16_t aKey) { mKey = aKey; }