Revert "media: uapi: HEVC: Add num_delta_pocs_of_ref_rps_idx field"

This reverts commit b6080257 which is
upstream commit ae440c5d.

It breaks the UAPI signature (but not the content), and it turns out is
not even needed for the 6.1.y tree at all, so revert it for now.

Bug: 161946584
Change-Id: I59e0a97dcaf1ee19bdffaf85f0c2a8f93dc82e75
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>