crypto: inside-secure - Fix unused variable warning when CONFIG_PCI=n

This patch fixes an unused variable warning from the compiler when the
driver is being compiled without PCI support in the kernel.

Fixes: 625f269a ("crypto: inside-secure - add support for...")
Signed-off-by: Pascal van Leeuwen <pvanleeuwen@verimatrix.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>