bus: ti-sysc: AM3: RNG is GP only

Make the RNG on AM3 GP only.

Based on this patch from TI v5.4 tree which is based on hwmod data
which are now removed:

| ARM: AM43xx: hwmod: Move RNG to a GP only links table
|
| On non-GP devices the RNG is controlled by the secure-side software,
| like in DRA7xx hwmod we should not control this IP when we are not
| a GP device.
|
| Signed-off-by: Andrew F. Davis <afd@ti.com>

Cc: stable@vger.kernel.org # v5.10+
Signed-off-by: Kevin Hilman <khilman@baylibre.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>