Provide support for the fan direction register.
This register shows configuration for system fans direction, which could
be forward or reversed.
For forward direction - relevant bit is set 0;
For reversed direction - relevant bit is set 1.

Signed-off-by: Vadim Pasternak <vadimp@mellanox.com>
Signed-off-by: Darren Hart (VMware) <dvhart@infradead.org>