Fix av1 dec doc page link issue

Signed-off-by: Carl Zhang <carl.zhang@intel.com>
diff --git a/doc/Makefile.am b/doc/Makefile.am
index 2ff3323..378aba1 100644
--- a/doc/Makefile.am
+++ b/doc/Makefile.am
@@ -44,6 +44,7 @@
 	$(VA_HEADER_DIR)/va_dec_jpeg.h	\
 	$(VA_HEADER_DIR)/va_dec_vp8.h	\
 	$(VA_HEADER_DIR)/va_dec_vp9.h	\
+	$(VA_HEADER_DIR)/va_dec_av1.h	\
 	$(VA_HEADER_DIR)/va_prot.h	\
 	$(VA_HEADER_DIR)/va_vpp.h	\
 	$(NULL)
diff --git a/doc/meson.build b/doc/meson.build
index bc15e2b..af3d218 100644
--- a/doc/meson.build
+++ b/doc/meson.build
@@ -16,6 +16,7 @@
   'va_dec_jpeg.h',
   'va_dec_vp8.h',
   'va_dec_vp9.h',
+  'va_dec_av1.h',
   'va_prot.h',
   'va_vpp.h'
 ]
diff --git a/va/va_dec_av1.h b/va/va_dec_av1.h
index f7299c4..c165f39 100644
--- a/va/va_dec_av1.h
+++ b/va/va_dec_av1.h
@@ -38,6 +38,14 @@
 extern "C" {
 #endif
 
+/**
+ * \defgroup api_dec_av1 AV1 decoding API
+ *
+ * This AV1 decoding API supports 8-bit/10bit 420 format only.
+ *
+ * @{
+ */
+
 /** Attribute value for VAConfigAttribDecAV1Features.
  *
  * This attribute decribes the supported features of a AV1