doc: Kconfig: `to be' -> `be'

Also, a comma was inserted to offset a modifier.
Signed-off-by: Michael Witten <mfwitten@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

crypto/Kconfig

@@ -354,7 +354,7 @@ config CRYPTO_RMD128
 	  RIPEMD-128 (ISO/IEC 10118-3:2004).
 
 	  RIPEMD-128 is a 128-bit cryptographic hash function. It should only
-	  to be used as a secure replacement for RIPEMD. For other use cases
+	  be used as a secure replacement for RIPEMD. For other use cases,
 	  RIPEMD-160 should be used.
 
 	  Developed by Hans Dobbertin, Antoon Bosselaers and Bart Preneel.