crypto: inside-secure - Remove #ifdef checks

When both PCI and OF are disabled, no drivers are registered, and
we get some unused-function warnings:

drivers/crypto/inside-secure/safexcel.c:1221:13: error: unused function 'safexcel_unregister_algorithms' [-Werror,-Wunused-function]
static void safexcel_unregister_algorithms(struct safexcel_crypto_priv *priv)
drivers/crypto/inside-secure/safexcel.c:1307:12: error: unused function 'safexcel_probe_generic' [-Werror,-Wunused-function]
static int safexcel_probe_generic(void *pdev,
drivers/crypto/inside-secure/safexcel.c:1531:13: error: unused function 'safexcel_hw_reset_rings' [-Werror,-Wunused-function]
static void safexcel_hw_reset_rings(struct safexcel_crypto_priv *priv)

It's better to make the compiler see what is going on and remove
such ifdef checks completely. In case of PCI, this is trivial since
pci_register_driver() is defined to an empty function that makes the
compiler subsequently drop all unused code silently.

The global pcireg_rc/ofreg_rc variables are not actually needed here
since the driver registration does not fail in ways that would make
it helpful.

For CONFIG_OF, an IS_ENABLED() check is still required, since platform
drivers can exist both with and without it.

A little change to linux/pci.h is needed to ensure that
pcim_enable_device() is visible to the driver. Moving the declaration
outside of ifdef would be sufficient here, but for consistency with the
rest of the file, adding an inline helper is probably best.

Fixes: 212ef6f2

 ("crypto: inside-secure - Fix unused variable warning when CONFIG_PCI=n")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>	# pci.h
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>