staging: r8188eu: use IW_HANDLER to declare wext handlers

Use the IW_HANDLER macro to declare the handler functions for
wext ioctls. We don't have to skip unused ioctl numbers manually.

The same modification was applied to the deprecated rtl8188eu driver in
commit af249fce ("staging: rtl8188eu: use IW_HANDLER to declare wext
handlers").

Signed-off-by: Martin Kaiser <martin@kaiser.cx>
Link: https://lore.kernel.org/r/20210807153636.11712-11-martin@kaiser.cx


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>