Dynamic Boost Control is a feature offered on AMD client platforms that
allows software to request and set power or frequency limits.

Only software that has authenticated with the PSP can retrieve or set
these limits.

Create a character device and ioctl for fetching the nonce. This ioctl
supports optionally passing authentication information which will influence
how many calls the nonce is valid for.
Acked-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>