msm: vidc: Add support for Hybrid Hier-P mode

Add support for hybrid hier-p mode encoding. This allows configuring
the number of layers in hybrid hier-p. This property enables Hier-p
encoding with fixed LTR referencing in each sub-GOP

Change-Id: I4b2a8ad4e4ae782df4e7a72429a64643196f2ae8
Signed-off-by: Ashray Kulkarni <ashrayk@codeaurora.org>