DEV: coccinelle: Add xalloc_size.cocci

This commits the Coccinelle patch to clean up sizeof handling for malloc/calloc.

dev/coccinelle/xalloc_size.cocci

@@ -0,0 +1,41 @@
+@@
+type T;
+expression E;
+expression t;
+@@
+
+(
+  t = calloc(E, sizeof(*t))
+|
+- t = calloc(E, sizeof(T))
++ t = calloc(E, sizeof(*t))
+)
+
+@@
+type T;
+T *x;
+@@
+
+  x = malloc(
+- sizeof(T)
++ sizeof(*x)
+  )
+
+@@
+type T;
+T *x;
+@@
+
+  x = calloc(1,
+- sizeof(T)
++ sizeof(*x)
+  )
+
+@@
+@@
+
+  calloc(
++ 1,
+  ...
+- ,1
+  )