[PATCH] selftests: nci: fix grammatical errors

[Xiang wangx]

Should not use unsigned expression compared with zero

Signed-off-by: Xiang wangx <wangxiang@xxxxxxxxxx>
---
 tools/testing/selftests/nci/nci_dev.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/testing/selftests/nci/nci_dev.c b/tools/testing/selftests/nci/nci_dev.c
index e1bf55dabdf6..162c41e9bcae 100644
--- a/tools/testing/selftests/nci/nci_dev.c
+++ b/tools/testing/selftests/nci/nci_dev.c
@@ -746,7 +746,7 @@ int read_write_nci_cmd(int nfc_sock, int virtual_fd, const __u8 *cmd, __u32 cmd_
 		       const __u8 *rsp, __u32 rsp_len)
 {
 	char buf[256];
-	unsigned int len;
+	int len;
 
 	send(nfc_sock, &cmd[3], cmd_len - 3, 0);
 	len = read(virtual_fd, buf, cmd_len);
-- 
2.20.1