coccinelle: add patch rule for dma_alloc_coherent

Commit dfd32cad ("dma-mapping: remove dma_zalloc_coherent()")
removed the definition of dma_zalloc_coherent() and also removed the
corresponding patch rule for replacing instances of dma_alloc_coherent +
memset in zalloc-simple.cocci (though left the report rule).

Add a new patch rule to remove unnecessary calls to memset after
allocating with dma_alloc_coherent. While we're at it, fix a couple of
typos.

Fixes: dfd32cad ("dma-mapping: remove dma_zalloc_coherent()")
Signed-off-by: Alex Dewar <alex.dewar90@gmail.com>
Signed-off-by: Julia Lawall <Julia.Lawall@inria.fr>

scripts/coccinelle/api/alloc/zalloc-simple.cocci

@@ -127,6 +127,16 @@ statement S;
   if ((x==NULL) || ...) S
 - memset((T2)x,0,E1);
 
+@depends on patch@
+type T, T2;
+expression x;
+expression E1,E2,E3,E4;
+statement S;
+@@
+  x = (T)dma_alloc_coherent(E1, E2, E3, E4);
+  if ((x==NULL) || ...) S
+- memset((T2)x, 0, E2);
+
 //----------------------------------------------------------
 //  For org mode
 //----------------------------------------------------------
@@ -199,9 +209,9 @@ statement S;
 position p;
 @@
 
- x = (T)dma_alloc_coherent@p(E2,E1,E3,E4);
+ x = (T)dma_alloc_coherent@p(E1,E2,E3,E4);
  if ((x==NULL) || ...) S
- memset((T2)x,0,E1);
+ memset((T2)x,0,E2);
 
 @script:python depends on org@
 p << r2.p;
@@ -217,7 +227,7 @@ p << r2.p;
 x << r2.x;
 @@
 
-msg="WARNING: dma_alloc_coherent use in %s already zeroes out memory,  so memset is not needed" % (x)
+msg="WARNING: dma_alloc_coherent used in %s already zeroes out memory, so memset is not needed" % (x)
 coccilib.report.print_report(p[0], msg)
 
 //-----------------------------------------------------------------