AM43xx has a spinlock module which is identical to the
one present on AM33xx. Register the spinlock ocp_if link
so that the spinlock hwmod and associated omap_device can
be instantiated, and the runtime pm API could be used by
the OMAP hwspinlock driver.

Cc: Rajendra Nayak <rnayak@ti.com>
Signed-off-by: Suman Anna <s-anna@ti.com>
Signed-off-by: Paul Walmsley <paul@pwsan.com>