gdb: add empty lines in loc.c
    
    I always found that some switch statements in this file were a bit too
    packed.  I think having empty lines between each case helps with
    reading.  I'm pushing this as obvious, I hope it won't be too
    controversial.
    
    gdb/ChangeLog:
    
    	* dwarf2/loc.c (decode_debug_loc_dwo_addresses): Add empty
    	lines.
    	(dwarf2_find_location_expression): Likewise.
    	(call_site_parameter_matches): Likewise.
    	(dwarf2_compile_expr_to_ax): Likewise.
    	(disassemble_dwarf_expression): Likewise.
    	(loclist_describe_location): Likewise.
    
    Change-Id: I381366a0468ff1793faa612c46ef48a9d4773192