crypto: af_alg - Fix incorrect boolean values in af_alg_ctx

Commit 1b34cbbf4f01 ("crypto: af_alg - Disallow concurrent writes in
af_alg_sendmsg") changed some fields from bool to 1-bit bitfields of
type u32.

However, some assignments to these fields, specifically 'more' and
'merge', assign values greater than 1. These relied on C's implicit
conversion to bool, such that zero becomes false and nonzero becomes
true.

With a 1-bit bitfields of type u32 instead, mod 2 of the value is taken
instead, resulting in 0 being assigned in some cases when 1 was intended.

Fix this by restoring the bool type.

Fixes: 1b34cbbf4f01 ("crypto: af_alg - Disallow concurrent writes in af_alg_sendmsg")
Cc: stable@vger.kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>