hwrng: core - Replace asm/uaccess.h by linux/uaccess.h

This patch fix the checkpatch warning about asm/uaccess.h.
In the same time, we sort the headers in alphabetical order.

Signed-off-by: Corentin Labbe <clabbe.montjoie@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>