pata_ninja32: Avoid corrupting status flags

Ninja32 needs to set some flags to indicate it does 32bit IO. However it currently assigns this which
loses the initializing flag and causes a warning spew. Fix it to use a logical or as is intended.

Signed-off-by: Alan Cox <alan@linux.intel.com>
Tested-by: Ellmar Stelnberger <estellnb@elstel.org>
Signed-off-by: Tejun Heo <tj@kernel.org>