Revert "ext4: require encryption feature for EXT4_IOC_SET_ENCRYPTION_POLICY"

Revert "ext4: require encryption feature for EXT4_IOC_SET_ENCRYPTION_POLICY"

This reverts commit e2968fb8e7980dccc199dac2593ad476db20969f.

For various reasons, we've had to start enforcing upstream that ext4
encryption can only be used if the filesystem superblock has the
EXT4_FEATURE_INCOMPAT_ENCRYPT flag set, as was the intended design.
Unfortunately, Android isn't ready for this quite yet, since its
userspace still needs to be updated to set the flag at mkfs time, or
else fix it later with tune2fs.  It will need some more time to be fixed
properly, so for now to avoid breaking some devices, revert the kernel
change.

Bug: 36231741
Signed-off-by: Eric Biggers <ebiggers@google.com>
Change-Id: I30bd54afb68dbaf9801f8954099dffa90a2f8df1