drivers/staging/mei/interface.c: take size of pointed value, not pointer

Sizeof a pointer-typed expression returns the size of the pointer, not that
of the pointed data.

The semantic patch that fixes this problem is as follows:
(http://coccinelle.lip6.fr/

)

// <smpl>
@@
expression *e;
type T;
identifier f;
@@

f(...,(T)e,...,
-sizeof(e)
+sizeof(*e)
,...)
// </smpl>

Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>