crypto: ccree - make cc_pm_{suspend,resume}() static

cc_pm_suspend() and cc_pm_resume() are not used outside
drivers/crypto/ccree/cc_pm.c.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>