bus: ti-sysc: allow reset sharing across devices

Some devices need to share their reset signals, like DSP MMUs, thus drop
the exclusive notation from reset request. Also, balance the init time
reset count, otherwise the resets will never be applied post boot.

Signed-off-by: Tero Kristo <t-kristo@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>