ANDROID: block: fix checking for wrapped key support

fscrypt isn't supposed to try to use inline encryption if the key is
wrapped but only blk-crypto-fallback is available.  This logic got lost
when updating to the latest inline encryption patchset.  Restore it in
blk_crypto_config_supported() where it should be now.

Also drop a redundant check from blk_crypto_fallback_bio_prep().

This fix should be folded into
ANDROID-block-add-hardware-wrapped-key-support.patch

Fixes: c2b86b72 ("FROMLIST: Update Inline Encryption from v6 to upstream version of patch series")
Change-Id: I4f8a32ee30d700b499da36e55e74d279a86bb779
Signed-off-by: Eric Biggers <ebiggers@google.com>