Remove struct keyword from range-based for loop
    
    The previous patch introduced this error with recent-ish GCCs:
    
    ../../binutils-gdb/gdb/remote.c: In function ‘int remote_add_target_side_condition(gdbarch*, bp_target_info*, char*, char*)’:
    ../../binutils-gdb/gdb/remote.c:9668:8: error: types may not be defined in a for-range-declaration [-Werror]
       for (struct agent_expr *aexpr : bp_tgt->conditions)
            ^~~~~~
    
    Removing the struct keyword fixes the error.
    
    gdb/ChangeLog:
    
    	* remote.c (remote_add_target_side_condition): Remove "struct"
    	keyword from range-based for loop.