Coccinelle: kzalloc-simple: Rename kzalloc-simple to zalloc-simple

Rename kzalloc-simple to zalloc-simple since now the rule is not
specific to kzalloc function only, but also to many other zero memory
allocating functions specified in the rule.
Suggested-by: NSF Markus Elfring <elfring@users.sourceforge.net>
Signed-off-by: NHimanshu Jha <himanshujha199640@gmail.com>
Acked-by: NJulia Lawall <julia.lawall@lip6.fr>
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>