batman-adv: correct several typ0s in the comments

Several typos have been corrected and some sentences have been rephrased

Signed-off-by: Antonio Quartulli <ordex@autistici.org>
Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>
diff --git a/net/batman-adv/bitarray.c b/net/batman-adv/bitarray.c
index c1f4bfc..0be9ff3 100644
--- a/net/batman-adv/bitarray.c
+++ b/net/batman-adv/bitarray.c
@@ -97,12 +97,12 @@
 			(seq_bits[i - word_num - 1] >>
 			 (WORD_BIT_SIZE-word_offset));
 		/* and the upper part of the right half and shift it left to
-		 * it's position */
+		 * its position */
 		/* for our example that would be: word[0] = 9800 + 0076 =
 		 * 9876 */
 	}
-	/* now for our last word, i==word_num, we only have the it's "left"
-	 * half. that's the 1000 word in our example.*/
+	/* now for our last word, i==word_num, we only have its "left" half.
+	 * that's the 1000 word in our example.*/
 
 	seq_bits[i] = (seq_bits[i - word_num] << word_offset);