nvme-tcp: fix kconfig dependency warning when !CRYPTO

When NVME_TCP is enabled and CRYPTO is disabled, it results in the
following Kbuild warning:

WARNING: unmet direct dependencies detected for CRYPTO_CRC32C
  Depends on [n]: CRYPTO [=n]
  Selected by [y]:
  - NVME_TCP [=y] && INET [=y] && BLK_DEV_NVME [=y]

The reason is that NVME_TCP selects CRYPTO_CRC32C without depending on or
selecting CRYPTO while CRYPTO_CRC32C is subordinate to CRYPTO.

Honor the kconfig menu hierarchy to remove kconfig dependency warnings.

Fixes: 79fd751d ("nvme: tcp: selects CRYPTO_CRC32C for nvme-tcp")
Signed-off-by: Necip Fazil Yildiran <fazilyildiran@gmail.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>