This patch adds a tristate EXT4_ENCRYPTION to do the selections
for EXT4_FS_ENCRYPTION because selecting from a bool causes all
the selected options to be built-in, even if EXT4 itself is a
module.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>