simple-pm-bus: Use -ENOSYS for checking missing system call

We don't need to check -ENOTSUPP since this is not used for this purpose
in U-Boot. Update the code accordingly.

Signed-off-by: Simon Glass <sjg@chromium.org>

Reviewed-by: Sean Anderson <seanga2@gmail.com>
diff --git a/drivers/core/simple-pm-bus.c b/drivers/core/simple-pm-bus.c
index 7a18953..1bb0d86 100644
--- a/drivers/core/simple-pm-bus.c
+++ b/drivers/core/simple-pm-bus.c
@@ -21,7 +21,7 @@
 		return ret;
 
 	ret = clk_enable_bulk(bulk);
-	if (ret && ret != -ENOSYS && ret != -ENOTSUPP) {
+	if (ret && ret != -ENOSYS) {
 		clk_release_bulk(bulk);
 		return ret;
 	}
@@ -34,7 +34,7 @@
 	struct clk_bulk *bulk = dev_get_priv(dev);
 
 	ret = clk_release_bulk(bulk);
-	if (ret && ret != -ENOSYS && ret != -ENOTSUPP)
+	if (ret && ret != -ENOSYS)
 		return ret;
 	else
 		return 0;