Coin: Move fix_ffmpeg_dependencies.sh to shared directory

Move fix_ffmpeg_dependencies.sh script from "linux" to "shared"
directory.

The script will be used on macOS but also on Windows (using MSYS2)

Task-number: QTBUG-122010
Change-Id: If63d5e3ba7562b230cce26c7bfba728a2ae0a382
Reviewed-by: Artem Dyomin <artem.dyomin@qt.io>
(cherry picked from commit b6c6812798)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

coin/provisioning/common/unix/install-ffmpeg-android.sh

@@ -99,7 +99,7 @@ build_ffmpeg_android() {
   rm -f "${openssl_libs}/libssl.so"
 
   if [[ "$shared" == "yes" ]]; then
-      fix_dependencies="${BASH_SOURCE%/*}/../linux/fix_ffmpeg_dependencies.sh"
+      fix_dependencies="${BASH_SOURCE%/*}/../shared/fix_ffmpeg_dependencies.sh"
       sudo "${fix_dependencies}" "${target_dir}" "${libs_prefix}" "no"
   fi
 

coin/provisioning/common/unix/install-ffmpeg.sh

@@ -86,7 +86,7 @@ if [ "$os" == "linux" ]; then
   output_dir="$ffmpeg_source_dir/build/installed/usr/local/$ffmpeg_name"
 
   if [ "$build_type" != "static" ]; then
-    fix_dependencies="${BASH_SOURCE%/*}/../linux/fix_ffmpeg_dependencies.sh"
+    fix_dependencies="${BASH_SOURCE%/*}/../shared/fix_ffmpeg_dependencies.sh"
     "$fix_dependencies" "$output_dir"
   fi