lavu/hwcontext_qsv: add loader field to AVQSVDeviceContext

In oneVPL, a valid mfxLoader handle is needed when creating mfx session
for decoding, encoding and processing[1], so add loader field to
AVQSVDeviceContext. User should fill this field before calling
av_hwdevice_ctx_init() if using oneVPL

This is in preparation for oneVPL support

[1]https://spec.oneapi.io/versions/latest/elements/oneVPL/source/programming_guide/VPL_prg_session.html#onevpl-dispatcher

doc/APIchanges

@@ -14,6 +14,9 @@ libavutil:     2021-04-27
 
 API changes, most recent first:
 
+2022-08-xx - xxxxxxxxxx - lavu 57.33.100 - hwcontext_qsv.h
+  Add loader field to AVQSVDeviceContext
+
 2022-08-03 - xxxxxxxxxx - lavu 57.32.100 - pixfmt.h
   Add AV_PIX_FMT_VUYA.
 

libavutil/hwcontext_qsv.h

@@ -34,6 +34,17 @@
  */
 typedef struct AVQSVDeviceContext {
     mfxSession session;
+    /**
+     * The mfxLoader handle used for mfxSession creation
+     *
+     * This field is only available for oneVPL user. For non-oneVPL user, this
+     * field must be set to NULL.
+     *
+     * Filled by the user before calling av_hwdevice_ctx_init() and should be
+     * cast to mfxLoader handle. Deallocating the AVHWDeviceContext will always
+     * release this interface.
+     */
+    void *loader;
 } AVQSVDeviceContext;
 
 /**

libavutil/version.h

@@ -79,8 +79,8 @@
  */
 
 #define LIBAVUTIL_VERSION_MAJOR  57
-#define LIBAVUTIL_VERSION_MINOR  32
-#define LIBAVUTIL_VERSION_MICRO 101
+#define LIBAVUTIL_VERSION_MINOR  33
+#define LIBAVUTIL_VERSION_MICRO 100
 
 #define LIBAVUTIL_VERSION_INT   AV_VERSION_INT(LIBAVUTIL_VERSION_MAJOR, \
                                                LIBAVUTIL_VERSION_MINOR, \