crypto: stm32/cryp - fix double pm exit

Delete extraneous lines in probe error handling code: pm was
disabled twice.

Fixes: 65f9aa36

 ("crypto: stm32/cryp - Add power management support")

Reported-by: Marek Vasut <marex@denx.de>
Signed-off-by: Nicolas Toromanoff <nicolas.toromanoff@foss.st.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>