Remove unnecessary "inline" marker introduced in commit 4be058fe.

Some of our older buildfarm members bleat about this coding,
along the lines of

prepjointree.c:112: warning: 'get_result_relid' declared inline after being called
prepjointree.c:112: warning: previous declaration of 'get_result_relid' was here

Modern compilers will probably inline this function without being
prompted, so rather than move the function, let's just drop the
marking.

src/backend/optimizer/prep/prepjointree.c

@@ -3026,7 +3026,7 @@ remove_useless_results_recurse(PlannerInfo *root, Node *jtnode)
  *		If jtnode is a RangeTblRef for an RTE_RESULT RTE, return its relid;
  *		otherwise return 0.
  */
-static inline int
+static int
 get_result_relid(PlannerInfo *root, Node *jtnode)
 {
 	int			varno;