power-domain: Rename free() to rfree()

This function name conflicts with our desire to #define free() to
something else on sandbox. Since it deals with resources, rename it to
rfree().

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Anatolij Gustschin <agust@denx.de>
diff --git a/drivers/power/domain/imx8-power-domain.c b/drivers/power/domain/imx8-power-domain.c
index aa76836..8e328f0 100644
--- a/drivers/power/domain/imx8-power-domain.c
+++ b/drivers/power/domain/imx8-power-domain.c
@@ -73,7 +73,7 @@
 
 struct power_domain_ops imx8_power_domain_ops_v2 = {
 	.request = imx8_power_domain_request,
-	.free = imx8_power_domain_free,
+	.rfree = imx8_power_domain_free,
 	.on = imx8_power_domain_on,
 	.off = imx8_power_domain_off,
 };