Fix installation location of kfontviewpart.rc

It looks like commit 8b297dbb (spotted by Albert Astals Cid), broke
this, the KAboutData object used KFI_NAME (which is "kfontinst"), which made
KxmlGui pick kfontviewpart.rc from ${KDE_INSTALL_KXMLGUI5DIR}/kfontinst.

Change the location to ${KDE_INSTALL_KXMLGUI5DIR}/kfontview, which is where
kfontviewui.rc is installed already.