staging: ks7010: utilize local variable

Function contains a local pointer variable defined to a memory location
within a structure. This memory location is later used by
dereferencing the struct instead of using the local pointer. The code
is cleaner if all references of the same memory location use the
local variable.

Utilize existing local pointer variable instead of dereferencing
struct.

Signed-off-by: Tobin C. Harding <me@tobin.cc>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>