Staging: rt2860/rt2870/rt3070/rt3090: fix compiler warning on x86_64

Staging: rt2860/rt2870/rt3070/rt3090: fix compiler warning on x86_64

When compiling rt2860/rt2870/rt3070 or rt3090 on x86_64, the following warning
is displayed:

drivers/staging/rt3090/rt_linux.c: In function 'duplicate_pkt':
drivers/staging/rt3090/rt_linux.c:531: warning: passing argument 1 of 'memmove' makes pointer from integer without a cast
include2/asm/string_64.h:58: note: expected 'void *' but argument is of type 'sk_buff_data_t'
drivers/staging/rt3090/rt_linux.c:533: warning: passing argument 1 of 'memmove' makes pointer from integer without a cast
include2/asm/string_64.h:58: note: expected 'void *' but argument is of type 'sk_buff_data_t'

The following patch fixes this warning.

Credits go to Helmut Schaa <hschaa@suse.de> for his kind advice/help on this
patch.

Signed-off-by: Axel Koellhofer <rain_maker@root-forum.org>
Cc: Helmut Schaa <hschaa@suse.de>
Acked-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>