hwspinlock: omap: Use index to get hwspinlock pointer

For loops with multiple initializers and increments are hard to read
and reason about, simplify this by using the looping index to index
into the hwspinlock array.

Signed-off-by: Andrew Davis <afd@ti.com>
Link: https://lore.kernel.org/r/20240208165114.63148-4-afd@ti.com


Signed-off-by: Bjorn Andersson <andersson@kernel.org>