geofield_field_formatter_view reworking switch code block

I get these notices

Notice: Undefined index: lat in geofield_field_formatter_view()
Notice: Undefined index: lon in geofield_field_formatter_view()

I've rewritten the switch code block and moved the foreach loop outside of it. I find the code easier to read as a result.

To fix the notices I make sure the lat/lon is not empty in the item.