resolve several possible null pointer dereference

resolve several possible null pointer dereference

issue detected by cppcheck

[channels/drive/client/drive_main.c:454] -> [channels/drive/client/drive_main.c:443]: (warning) Either the condition '!irp' is redundant or there is possible null pointer dereference: irp.
[client/X11/xf_window.c:582] -> [client/X11/xf_window.c:580]: (warning) Either the condition '!xfc' is redundant or there is possible null pointer dereference: xfc.
[winpr/libwinpr/path/test/TestPathShell.c:40] -> [winpr/libwinpr/path/test/TestPathShell.c:43]: (warning) Either the condition '!path' is redundant or there is possible null pointer dereference: path.
[winpr/libwinpr/path/test/TestPathShell.c:49] -> [winpr/libwinpr/path/test/TestPathShell.c:52]: (warning) Either the condition '!path' is redundant or there is possible null pointer dereference: path.