module: Do not paper over type mismatches in module_param_call()

The module_param_call() macro was explicitly casting the .set and
.get function prototypes away. This can lead to hard-to-find type
mismatches. Now that all the function prototypes have been fixed
tree-wide, we can drop these casts, and use named initializers too.

Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Jessica Yu <jeyu@kernel.org>