usb: sisusb: remove useless macros and compact the code

Remove macros which are only wrappers around standard operations. When
we expand them into code, we see that sisusbcon_memsetw can simply use
memset16 and sisusbcon_putcs can just call memcpy. So make the code
compact.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>