drm/i915/gvt: remove skl_misc_ctl_write handler

drm/i915/gvt: remove skl_misc_ctl_write handler

With different settings of compressed data hash mode between VMs and host
may cause gpu issues.

Commit: 2b6a162d4 ("drm/i915/gvt: Disable compression workaround for Gen9")
disable compression workaround of guest in gvt host to align with host.

Commit: 0dad5bff3 ("drm/i915: Switch over to the LLC/eLLC hotspot avoidance
hash mode for CCS") add compression workaround, then we can remove the
skl_misc_ctl_write hanlder.

Better solution should be always keeping same settings as host, and bypass
the write request from VMs, but it need to fetch data from host's
"Context".

Cc: Zhi Wang <zhi.a.wang@intel.com>
Signed-off-by: Weinan Li <weinan.z.li@intel.com>
Signed-off-by: Xiong Zhang <xiong.y.zhang@intel.com>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>