[buteo-mtp] Fix unable of copy big files to SD card over MTP. Fixes J…

…B#50733.

The problem is unable to copy big file (more 300 Mb) from host PC
to SD card over MTP. At Linux after about 1-2 minutes from start:
"libmtp error: Could not send object property list".
Files appears but MD sums are not matched.
At Windows on laptop: after about 1-2 minutes the copy progress
bar disappears without any notification.

It seems that ftruncate (called
from fsstorageplugin.cpp:1305
...
if( !file.resize(size))
...
for big file continues too long, because it tries to fill memory
on SD with zeros.
strace -r /usr/lib/mtp/mtp_service
...
0.000400 ftruncate64(21, 584411895) = 0
124.915724 close(21)                 = 0
...
So PC host close connection by timeout.

For resolve this issue we can use another method memory allocation.

mts/platform/storage/fsstorageplugin/fsstorageplugin.cpp

@@ -2,6 +2,7 @@
 * This file is part of libmeegomtp package
 *
 * Copyright (C) 2010 Nokia Corporation. All rights reserved.
+* Copyright (c) 2020 Open Mobile Platform LLC.
 *
 * Contact: Deepak Kodihalli <deepak.kodihalli@nokia.com>
 *
@@ -41,6 +42,7 @@
 #include <sys/time.h>
 #include <unistd.h>
 #include <errno.h>
+#include <fcntl.h>
 
 #include <QDebug>
 #include <QFile>
@@ -1032,7 +1034,7 @@ MTPResponseCode FSStoragePlugin::createFile( const QString &path, MTPObjectInfo
     /* Resize to expected content length */
     quint64 size = info ? info->mtpObjectCompressedSize : 0;
 
-    if( !file.resize(size) ) {
+    if( fallocate(file.handle(), 0, 0, size) ) {
         MTP_LOG_WARNING("failed to set file:" << path << " to size:" << size);
     }