libs: encoder: h265: fix reserved length of bits
libs: encoder: h265: fix reserved length of bits

Fix reserved length of bits for bit_depth_luma_minus8 and bit_depth_chroma_minus8

https://bugzilla.gnome.org/show_bug.cgi?id=778749

GStreamer/gstreamer-vaapi,ceyusa/gstreamer-vaapi,ceyusa/gstreamer-vaapi,GStreamer/gstreamer-vaapi