drm/i915/huc: fix intel_huc.c doc bulleted list format error

Fix the following make htmldocs errors/warnings:

./drivers/gpu/drm/i915/gt/uc/intel_huc.c:29: ERROR: Unexpected indentation.
./drivers/gpu/drm/i915/gt/uc/intel_huc.c:30: WARNING: Block quote ends without a blank line; unexpected unindent.
./drivers/gpu/drm/i915/gt/uc/intel_huc.c:35: WARNING: Bullet list ends without a blank line; unexpected unindent.

This output is a bit misleading. The real issue here is we need a blank
line before and after the bulleted list.

Link: https://www.kernel.org/doc/html/latest/gpu/i915.html#huc
Link: https://lore.kernel.org/dri-devel/20230530152958.1384061-1-daniele.ceraolospurio@intel.com/Signed-off-by: David Reaver <me@davidreaver.com>
Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230727025400.372965-1-me@davidreaver.com

drivers/gpu/drm/i915/gt/uc/intel_huc.c

@@ -26,6 +26,7 @@
  * The kernel driver is only responsible for loading the HuC firmware and
  * triggering its security authentication. This is done differently depending
  * on the platform:
+ *
  * - older platforms (from Gen9 to most Gen12s): the load is performed via DMA
  *   and the authentication via GuC
  * - DG2: load and authentication are both performed via GSC.
@@ -33,6 +34,7 @@
  *   not-DG2 older platforms), while the authentication is done in 2-steps,
  *   a first auth for clear-media workloads via GuC and a second one for all
  *   workloads via GSC.
+ *
  * On platforms where the GuC does the authentication, to correctly do so the
  * HuC binary must be loaded before the GuC one.
  * Loading the HuC is optional; however, not using the HuC might negatively