pci: avoid memory leak

strdup uses malloc to allocate memory for str.
If we cannot bind to the generic driver we should release
the memory.

The problem was indicated by clang scan-build.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/drivers/pci/pci-uclass.c b/drivers/pci/pci-uclass.c
index 40f59c0..504d7e3 100644
--- a/drivers/pci/pci-uclass.c
+++ b/drivers/pci/pci-uclass.c
@@ -660,6 +660,7 @@
 	ret = device_bind_driver(parent, drv, str, devp);
 	if (ret) {
 		debug("%s: Failed to bind generic driver: %d\n", __func__, ret);
+		free(str);
 		return ret;
 	}
 	debug("%s: No match found: bound generic driver instead\n", __func__);