staging: r8188eu: remove usb buffer macros

Remove two unused macros that allocate and free usb buffers.
Signed-off-by: Martin Kaiser <martin@kaiser.cx>
Tested-by: Philipp Hortmann <philipp.g.hortmann@gmail.com> # Edimax N150
Link: https://lore.kernel.org/r/20230111195640.306748-17-martin@kaiser.cxSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/r8188eu/include/rtw_io.h

@@ -16,12 +16,6 @@
 #include <linux/usb.h>
 #include <linux/usb/ch9.h>
 
-#define rtw_usb_buffer_alloc(dev, size, dma)				\
-	usb_alloc_coherent((dev), (size), (in_interrupt() ?		\
-			   GFP_ATOMIC : GFP_KERNEL), (dma))
-#define rtw_usb_buffer_free(dev, size, addr, dma)			\
-	usb_free_coherent((dev), (size), (addr), (dma))
-
 struct intf_priv;
 struct intf_hdl;