Fix one checkstyle and one compile error caused by the last commit

buffer/src/main/java/io/netty/buffer/PooledUnsafeDirectByteBuf.java

@@ -16,6 +16,7 @@
 
 package io.netty.buffer;
 
+import io.netty.util.internal.PlatformDependent;
 import sun.misc.Unsafe;
 
 import java.io.IOException;
@@ -57,7 +58,7 @@ final class PooledUnsafeDirectByteBuf extends PooledByteBuf<ByteBuffer> {
             if (addressField.getLong(directBuf) == 0) {
                 throw new Error("direct buffer address must be non-zero");
             }
-            UnpooledDirectByteBuf.freeDirect(directBuf);
+            PlatformDependent.freeDirectBuffer(directBuf);
         } catch (Throwable t) {
             throw new Error(t);
         }

common/src/main/java/io/netty/util/internal/PlatformDependent0.java

@@ -96,7 +96,6 @@ final class PlatformDependent0 {
         return UNSAFE.objectFieldOffset(field);
     }
 
-
     private PlatformDependent0() {
     }
 }