core: Fix typo in xavp header file

- Corrected avpx_free to xavp_free
(cherry picked from commit c1b486d199349efc931975dc90924962e8b2b353)

xavp.h

@@ -70,7 +70,7 @@ typedef struct _sr_xavp {
 } sr_xavp_t;
 
 int xavp_init_head(void);
-void avpx_free(sr_xavp_t *xa);
+void xavp_free(sr_xavp_t *xa);
 
 int xavp_add(sr_xavp_t *xavp, sr_xavp_t **list);
 int xavp_add_last(sr_xavp_t *xavp, sr_xavp_t **list);