9p: fix memleak in fs/9p/v9fs.c

This patch fixes a memory leak introduced by
commit ba17674fe02909fef049fd4b620a2805bdb8c693.

Spotted by the Coverity checker.

Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
diff --git a/fs/9p/v9fs.c b/fs/9p/v9fs.c
index 873802d..756f7e9 100644
--- a/fs/9p/v9fs.c
+++ b/fs/9p/v9fs.c
@@ -162,6 +162,7 @@
 				if (*e != '\0')
 					v9ses->uid = ~0;
 			}
+			kfree(s);
 			break;
 
 		default: