crypto: ixp4xx - include fix

Before commit de477254

 ("include: replace
linux/module.h with "struct module" wherever possible") <linux/module.h> was
implicitly included through <linux/platform_device.h> -> <linux/device.h>.

Signed-off-by: Michał Wróbel <michal.wrobel@flytronic.pl>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>