anv: Avoid corrupting indirect depth clear values

anv: Avoid corrupting indirect depth clear values

We don't need to initialize the BO since blorp updates the clear color
BO content with fast clear value i.e ANV_HZ_FC_VAL for depth surface.

With this approach, we can get rid of possibility of corruption since we
are no longer sharing the same clear BO for depth formats.

Closes: #3614

Signed-off-by: Sagar Ghuge <sagar.ghuge@intel.com>
Reviewed-by: Nanley Chery <nanley.g.chery@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/9941>