ARM: AM33xx+: hwmod: re-use omap4 implementations for reset functionality

The reset code functionality is mostly a copy paste between OMAP4+ and
AM33xx+. Re-use the omap4 code where possible, and just keep the special
implementation for de-asserting the hardreset lines for AM33xx, as
AM33xx+ devices have slightly different register layouts compared to
OMAP4+. This patch also fixes the hardreset issues faced on AM43xx.

Signed-off-by: Tero Kristo <t-kristo@ti.com>
Reported-by: Dave Gerlach <d-gerlach@ti.com>
Reported-by: Suman Anna <s-anna@ti.com>
Signed-off-by: Paul Walmsley <paul@pwsan.com>