soc: ti: k3-navss-ringacc: Add AM64 ringacc support

soc: ti: k3-navss-ringacc: Add AM64 ringacc support

AM64 dual mode rings are modeled as pair of Rings objects which has common
configuration and memory buffer, but separate real-time control register
sets for each direction mem2dev (forward) and dev2mem (reverse).

AM64 rings must be requested only using k3_ringacc_request_rings_pair(),
and forward ring must always be initialized/configured. After this any
other Ringacc APIs can be used without any callers changes.

Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>