ARM: OMAP2+: hwmod: Change hardreset soc_ops for AM43XX

am43xx reset register layout is more similar to am33xx than omap4 so
use the am33xx functions for hwmod hardreset soc_ops rather than the
currently used omap4 functions. Without this, assert_hardreset and
deassert_hardreset will not work on am43xx.

Signed-off-by: Dave Gerlach <d-gerlach@ti.com>
[paul@pwsan.com: fixed build errors for an AM43xx-only Kconfig]
Signed-off-by: Paul Walmsley <paul@pwsan.com>