drm/i915/gvt: Add F_CMD_ACCESS for some GEN9 SKU WA MMIO access

Without F_CMD_ACCESS, guest LRI cmd will fail due to "access to
non-render register" when init below WAs:
WaDisableDynamicCreditSharing: GAMT_CHKN_BIT_REG
WaCompressedResourceSamplerPbeMediaNewHashMode: MMCD_MISC_CTRL

So add F_CMD_ACCESS to the two MMIO.

Reviewed-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Signed-off-by: Colin Xu <colin.xu@intel.com>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20200819010801.53411-1-colin.xu@intel.com