Staging: speakup: Use ARRAY_SIZE macro

ARRAY_SIZE is more concise to use when the size of an array is divided
by the size of its type or the size of its first element.

Changes made using Coccinelle-

@@
type T;
T[] E;
@@

- (sizeof(E)/sizeof(T))
+ ARRAY_SIZE(E)

Signed-off-by: Shraddha Barke <shraddha.6596@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>