keys: Fix grammar and formatting in 'struct key_type' comments

s/it/if/ and s/revokation/revocation/, capitalize "clear", and add a
period after the sentence. Fix the comment formatting.

Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>

Author: toblux

include/linux/key-type.h

@@ -107,11 +107,14 @@ struct key_type {
 	 */
 	int (*match_preparse)(struct key_match_data *match_data);
 
-	/* Free preparsed match data (optional).  This should be supplied it
-	 * ->match_preparse() is supplied. */
+	/*
+	 * Free preparsed match data (optional).  This should be supplied if
+	 * ->match_preparse() is supplied.
+	 */
 	void (*match_free)(struct key_match_data *match_data);
 
-	/* clear some of the data from a key on revokation (optional)
+	/*
+	 * Clear some of the data from a key on revocation (optional).
 	 * - the key's semaphore will be write-locked by the caller
 	 */
 	void (*revoke)(struct key *key);