staging: rtl8192u: remove unnecessary line continuations in r819xU_cmdpkt.c

This patch fixes the following checkpatch warning:
WARNING: Avoid unnecessary line continuations

Signed-off-by: Xenia Ragiadakou <burzalodowa@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>