drm/i915/gvt: fix intel_vgpu_alloc_resource() kernel-doc parameter

drivers/gpu/drm/i915/gvt/aperture_gm.c:344: warning: Function parameter or member 'conf' not described in 'intel_vgpu_alloc_resource'
drivers/gpu/drm/i915/gvt/aperture_gm.c:344: warning: Excess function parameter 'param' description in 'intel_vgpu_alloc_resource'

Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/9213214c9caa296ebd349a5d5b44c2bbb45cdf99.1683041799.git.jani.nikula@intel.com