fix unaligned exception in /drivers/net/wireless/orinoco.c

Prevent an unaligned exception to occur.  (GCC 4.1) tmp is defined as char
pointer while it is later accessed as short.

Cc: Jean Tourrilhes <jt@hpl.hp.com>
Cc: John W. Linville <linville@tuxdriver.com>
Cc: Jeff Garzik <jeff@garzik.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jeff Garzik <jeff@garzik.org>