oxnas: sata_oxnas: refactoring phase 1

locking for 2nd port and hwraid was added from vendor's GPL code which
doesn't comply with current kernel coding style.

 - moved all global variables into host_priv
 - renamed locks
 - sanetized acquire() and release() parameter list

Signed-off-by: Daniel Golle <daniel@makrotopia.org>

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@43766 3c298f89-4303-0410-b956-a3cf2f4a3e73