drm/i915/gem/i915_gem_create: Provide the function names for proper kerneldoc headers

Fixes the following W=1 kernel build warning(s):

 drivers/gpu/drm/i915/gem/i915_gem_create.c:147: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst
 drivers/gpu/drm/i915/gem/i915_gem_create.c:218: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst
 drivers/gpu/drm/i915/gem/i915_gem_create.c:402: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst

Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: David Airlie <airlied@gmail.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Matthew Auld <matthew.auld@intel.com>
Cc: intel-gfx@lists.freedesktop.org
Cc: dri-devel@lists.freedesktop.org
Signed-off-by: Lee Jones <lee@kernel.org>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
[Jani: fixed i915_gem_create_ext_ioctl while applying]
Link: https://patchwork.freedesktop.org/patch/msgid/20230331092607.700644-8-lee@kernel.org

drivers/gpu/drm/i915/gem/i915_gem_create.c

@@ -143,7 +143,8 @@ __i915_gem_object_create_user_ext(struct drm_i915_private *i915, u64 size,
 }
 
 /**
- * Creates a new object using the same path as DRM_I915_GEM_CREATE_EXT
+ * __i915_gem_object_create_user - Creates a new object using the same path as
+ *                                 DRM_I915_GEM_CREATE_EXT
  * @i915: i915 private
  * @size: size of the buffer, in bytes
  * @placements: possible placement regions, in priority order
@@ -214,7 +215,7 @@ i915_gem_dumb_create(struct drm_file *file,
 }
 
 /**
- * Creates a new mm object and returns a handle to it.
+ * i915_gem_create_ioctl - Creates a new mm object and returns a handle to it.
  * @dev: drm device pointer
  * @data: ioctl data blob
  * @file: drm file pointer
@@ -398,7 +399,7 @@ static const i915_user_extension_fn create_extensions[] = {
 };
 
 /**
- * Creates a new mm object and returns a handle to it.
+ * i915_gem_create_ext_ioctl - Creates a new mm object and returns a handle to it.
  * @dev: drm device pointer
  * @data: ioctl data blob
  * @file: drm file pointer