staging: r8188eu: remove RT_TRACE prints from usb_ops_linux.c

We should use the standard mechanism for debug prints. Remove the prints
that use driver-specific macros.

Signed-off-by: Martin Kaiser <martin@kaiser.cx>
Link: https://lore.kernel.org/r/20210807153636.11712-3-martin@kaiser.cx


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