MAINTAINERS: make me a reviewer of USB/IP

I think I am familiar enough with USB/IP and is adequate as a reviewer.

Every time there is some patch/bug, I wish I can get pinged
and I will feedback on that.

I had some contributions to USBIP and some support for it.

Contribution:
Commit 17af79321 ("docs: usbip: Fix major fields and
    descriptions in protocol")
Commit b737eecd4 ("usbip: tools: add options and examples
    in man page related to device mode")
Commit a58977b2f ("usbip: tools: add usage of device mode in
    usbip_list.c")

Support:
Commit 8f36b3b4e1 ("usbip: add USBIP_URB_* URB transfer flags")
Bug report: https://lore.kernel.org/lkml/ZBHxfUX60EyCMw5l@Sun/

I also have implemented a userspace usbip server in
https://github.com/canokeys/canokey-usbip
and maintain a list of usbip implementations
https://github.com/usbip/implementations

Signed-off-by: Hongren (Zenithal) Zheng <i@zenithal.me>
Acked-by: Shuah Khan <skhan@linuxfoundation.org>
Link: https://lore.kernel.org/r/ZBIBCRiFGSqQcOon@Sun
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

MAINTAINERS

@@ -21651,6 +21651,7 @@ USB OVER IP DRIVER
 M:	Valentina Manea <valentina.manea.m@gmail.com>
 M:	Shuah Khan <shuah@kernel.org>
 M:	Shuah Khan <skhan@linuxfoundation.org>
+R:	Hongren Zheng <i@zenithal.me>
 L:	linux-usb@vger.kernel.org
 S:	Maintained
 F:	Documentation/usb/usbip_protocol.rst