msm: ipa: fix potential NULL pointer dereference

This dereference can happen in error leg of ipa_reset_hdr.

Change-Id: Id060c978a2aaa88ab6bce2efb3c81a007e2d2292
Signed-off-by: Ravi Gummadidala <rgummadi@codeaurora.org>
diff --git a/drivers/platform/msm/ipa/ipa_hdr.c b/drivers/platform/msm/ipa/ipa_hdr.c
index 9618da2..54cbf5f 100644
--- a/drivers/platform/msm/ipa/ipa_hdr.c
+++ b/drivers/platform/msm/ipa/ipa_hdr.c
@@ -450,8 +450,11 @@
 			continue;
 
 		node = ipa_search(&ipa_ctx->hdr_hdl_tree, (u32) entry);
-		if (node == NULL)
+		if (node == NULL) {
 			WARN_ON(1);
+			mutex_unlock(&ipa_ctx->lock);
+			return -EFAULT;
+		}
 		list_del(&entry->link);
 		entry->cookie = 0;
 		kmem_cache_free(ipa_ctx->hdr_cache, entry);