lib: Drop SHA512_ALGO in lieu of SHA512

SHA512_ALGO was used as a "either SHA512 or SHA384", although the
implementations of these two algorithms share a majority of code.

From a Kconfig interface perspective, it makes sense to present two
distinct options. This requires #ifdefing out the SHA512
implementation from sha512.c. The latter doesn't make any sense.

It's reasonable to say in Kconfig that SHA384 depends on SHA512, and
seems to be the more polite way to handle the selection.

Thus, automatically select SHA512 when SHA384 is enabled.

Signed-off-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
diff --git a/lib/crypt/Kconfig b/lib/crypt/Kconfig
index 5495ae8..6a50029 100644
--- a/lib/crypt/Kconfig
+++ b/lib/crypt/Kconfig
@@ -20,7 +20,7 @@
 config CRYPT_PW_SHA512
 	bool "Provide sha512crypt"
 	select SHA512
-	select SHA512_ALGO
+	select SHA512
 	help
 	  Enables support for the sha512crypt password-hashing algorithm.
 	  The prefix is "$6$".