Fix folder name by using workaround (rename files to the correct directory) using :
git mv -f mediaportal/mediaportal.base/LastFMHelper.dll mediaportal/MediaPortal.Base/LastfmHelper.dll
git mv -f mediaportal/mediaportal.base/skin/Titan/myrss.xml mediaportal/MediaPortal.Base/skin/Titan/myRSS.xml
git mv -f mediaportal/mediaportal.base/skin/Titan/DialogNotifyLastFM.xml mediaportal/MediaPortal.Base/skin/Titan/DialogNotifyLastfm.xml
git mv -f mediaportal/mediaportal.base/skin/Titan/Media/Last.fm_Logo_Black.png mediaportal/MediaPortal.Base/skin/Titan/Media/Last.FM_Logo_Black.png
When merging Master branch to your branch, you will need to delete your 4 local above files then the merge will be ok and the branch will be corrected.