staging: r8188eu: ctrl vendor req value is always 0x05

staging: r8188eu: ctrl vendor req value is always 0x05

The bRequest value for the vendor specific control requests sent by this
driver is always 0x05. Replace the function parameter with the define from
usb_ops.h.

This patch is an adaptation of commit eeb4661560ff ("staging: rtl8188eu:
ctrl vendor req value is always 0x05") for the new r8188eu driver.

Acked-by: Phillip Potter <phil@philpotter.co.uk>
Signed-off-by: Martin Kaiser <martin@kaiser.cx>
Link: https://lore.kernel.org/r/20210818200041.10870-1-martin@kaiser.cx
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>