orinoco: firmware: consistently compile out fw cache support if not requested

Currently part of support for FW caching is unconditionally compiled
in even if it is never used. Consistently remove caching support if
not requested by user.

Signed-off-by: Andrey Borzenkov <arvidjaar@mail.ru>
Signed-off-by: John W. Linville <linville@tuxdriver.com>