use ngx_pmemalign() to allocate radix pages

src/core/ngx_radix_tree.c

diff --git a/src/core/ngx_radix_tree.c b/src/core/ngx_radix_tree.c
index b94b4b7..050dac0 100644
--- a/src/core/ngx_radix_tree.c
+++ b/src/core/ngx_radix_tree.c
@@ -274,7 +274,7 @@
     }
 
     if (tree->size < sizeof(ngx_radix_node_t)) {
-        tree->start = ngx_palloc(tree->pool, ngx_pagesize);
+        tree->start = ngx_pmemalign(tree->pool, ngx_pagesize, ngx_pagesize);
         if (tree->start == NULL) {
             return NULL;
         }