clock-mmss-8994: Add parent for oxili_gfx3d_clk

oxili_gfx3d_clk has an external parent provided by clock-rpm-8994.
Get the parent from clock-rpm-8994 controller during probe.

Also add measurement support for oxili_gfx3d_clk.

Change-Id: Ibabf1470b94e35efe61a3c205f07e840c27dbb6e
Signed-off-by: Junjie Wu <junjiew@codeaurora.org>